One thing I never thought about as a kid was how deliberate Pokémon names are. They look like nonsense words, but almost every one is two real words mashed together, usually describing what the creature is and what it does. Charmander is a good example. It is char, as in charred or charcoal, plus salamander. Once you see the pattern you cannot stop seeing it.
So I went through the original 151 and wrote down where each name comes from. Most of these are confirmed on Bulbapedia, which credits the actual designers and translators where it can. A few are educated guesses since the localization team has never spelled them all out. Here is the whole Kanto dex, in order.
The starters and the first evolutions
Bulbasaur is bulb plus saur, the dinosaur suffix you see all over this list. Ivysaur swaps in ivy, and Venusaur points at the Venus flytrap. The Charmander line is char plus salamander, then char plus chameleon, then char plus lizard for Charizard.
Squirtle is squirt plus turtle. Wartortle mixes warty or war with tortoise, and Blastoise is blast plus tortoise, which fits the water cannons on its shell.
Bugs and early birds
Caterpie is caterpillar, Metapod is metamorphosis plus pod, and Butterfree is butterfly plus free. Weedle is weed or worm plus needle, Kakuna comes from the word cocoon, and Beedrill is bee plus drill.
Pidgey, Pidgeotto, and Pidgeot all build off pigeon, with Pidgeot leaning on jet at the end. Spearow is sparrow plus spear, and Fearow adds fear. Rattata is rat with a stutter for speed, and Raticate is rat plus eradicate.
Snakes, mice, and the early staples
Ekans is snake spelled backwards, and Arbok is cobra backwards, give or take a letter. Pikachu blends pika, an onomatopoeia for a sparking sound, with chu, the Japanese squeak a mouse makes. Raichu swaps in rai, the Japanese word for thunder.
Sandshrew and Sandslash are sand plus shrew and sand plus slash. The Nidoran families come from needle, with the suffixes marking queen and king at the top of each line. Clefairy is a musical clef plus fairy, and Clefable adds fable.
Foxes, balloons, and bats
Vulpix is vulpes, the Latin for fox, plus six for its tails. Ninetales is nine plus tales, a pun on tails. Jigglypuff is jiggly plus puff, and Wigglytuff is wiggly plus tuft.
Zubat and Golbat lean on bat, with Golbat picking up gulp or ghoul. Oddish is odd plus radish, Gloom is just gloom for its miserable face, and Vileplume is vile plus plume.
Parasites, moles, and cats
Paras and Parasect come from parasite, with Parasect adding insect. Venonat is venom plus gnat, and Venomoth is venom plus moth. Diglett is dig plus a small diminutive, and Dugtrio is dug plus trio for the three heads.
Meowth is the meow sound, Persian is the cat breed, Psyduck is psychic plus duck, and Golduck is gold plus duck. Mankey mixes monkey with angry, and Primeape is prime plus ape, also a nod to its rage.
Dogs, tadpoles, and magicians
Growlithe is growl plus lithe, and Arcanine is arcane plus canine. The Poliwag line all come from polliwog, an old word for tadpole, plus wag, whirl, and wrath.
Abra, Kadabra, and Alakazam are pulled straight from abracadabra and alakazam, the classic magic words. The Machop line is macho plus chop, choke, and champion.
Plants, jellyfish, and rocks
Bellsprout is bell plus sprout, Weepinbell is weeping plus bell, and Victreebel is victory plus bell. Tentacool and Tentacruel are tentacle plus cool and tentacle plus cruel.
Geodude is geo, meaning earth, plus dude. Graveler is gravel plus traveler, and Golem is just golem. Onix is a spelling of onyx, the stone.
Horses, sloths, and magnets
Ponyta is pony with a tail flourish, and Rapidash is rapid plus dash. Slowpoke is the everyday word for someone slow, and Slowbro is slow plus bro. Magnemite is magnet plus mite, and Magneton is magnet plus the idea of electrons.
Farfetch'd is the phrase far-fetched, which is also a joke about the leek it carries. Doduo is dodo plus duo for two heads, and Dodrio is dodo plus trio for three.
Sea life and sludge
Seel is a play on seal, and Dewgong is dew plus dugong, the sea cow. Grimer is grime and Muk is muck. Shellder is shell, and Cloyster mixes cloister with oyster.
Gastly is ghastly plus gas, Haunter is haunt, and Gengar comes from doppelganger. Drowzee is drowsy, and Hypno is hypnosis.
Crabs, eggs, and bones
Krabby is crab plus crabby, and Kingler is king plus a crab ending. Voltorb is volt plus orb, and Electrode is the actual electrical term. Exeggcute is execute plus egg, and Exeggutor is executor plus egg.
Cubone is cub plus bone, fitting the skull it wears, and Marowak is marrow plus a whacking sound for its club. Hitmonlee honors Bruce Lee with his kicks, and Hitmonchan honors Jackie Chan with his punches.
Tongues, gas, and rhinos
Lickitung is lick plus tongue. Koffing is coughing and Weezing is wheezing, both spelled to fit the poison gas theme. Rhyhorn is rhino plus horn, and Rhydon is rhino plus the don dinosaur suffix.
Chansey comes from chance, since it is famously lucky to find. Tangela is tangle, and Kangaskhan is kangaroo plus Genghis Khan.
Seahorses, fish, and stars
Horsea is horse plus sea, a literal seahorse, and Seadra is sea plus dragon. Goldeen and Seaking play on goldfish and a regal king. Staryu and Starmie are star plus you and star plus me, which is a cute pair.
Mr. Mime is exactly what it sounds like, a mime. Scyther is the scythe blades on its arms, and Jynx is a spelling of jinx.
Fighters of the electric and fire kind
Electabuzz is electric plus buzz, and Magmar comes from magma. Pinsir is a respelling of pincer, and Tauros is the Latin Taurus, the bull. Magikarp is magic plus carp, a joke since the fish does almost nothing.
Gyarados and Lapras keep their Japanese roots and have never been pinned to a single clean source, which is part of their charm. Ditto is the word ditto, meaning a copy, which matches its whole gimmick.
Eevee and its evolutions
Eevee comes from the letters E and V, short for evolution, since it can branch so many ways. Vaporeon, Jolteon, and Flareon are vapor, jolt, and flare, each plus the eon suffix shared across the family.
Porygon is a respelling of polygon, a nod to it being the first digital Pokémon. It is one of the rare names that describes the art style rather than an animal.
Fossils and the legendary finish
Omanyte and Omastar come from ammonite, the spiral fossil, with Omastar adding star. Kabuto is the Japanese word for a samurai helmet, and Kabutops adds tops. Aerodactyl is aero plus pterodactyl.
Snorlax is snore plus lax, as in relaxed. The legendary birds end in the Spanish numbers, so Articuno is arctic plus uno, Zapdos is zap plus dos, and Moltres is molten plus tres.
Dratini, Dragonair, and Dragonite all come from dragon, with air and a mineral ending. Mewtwo is Mew plus two, since it is the clone, and Mew itself is thought to come from the cat sound and the idea of something new and rare.
Why this is worth knowing
None of this changes how you play, but it makes the names stick. Once you know Charmander is charred plus salamander, you never forget which one it is. The same trick works for guessing games. If a clue points at fire and a lizard, the name probably says so too.
If you want to test how many you actually remember, the daily puzzles on Pokédle lean on exactly this kind of recall. Knowing the why behind a name is a surprisingly good shortcut to the answer.