Their English name seems to be a portmanteau of "dinosaur" and "mist", referring to their dinosaur-like appearance and WATER Attribute. The Japanese names indicates a word play with "Dynamo" instead, referring to their Machine-Type. Both appear to be correct, as the archetype seems to make references to both "dinosaurs" and "dynamo". It can also be a pun on "dynamis" ("δύναμις", also transliterated as "dunamis"), the Greek word for "power" or "strength".
"Dinomist" cards cater to aggressive players, focusing on amassing multiple monsters through Pendulum Summon while preventing their opponent from countering them via support from the Pendulum Zones. All Scale 3 "Dinomists" have the Pendulum Effect "If another "Dinomist" card(s) you control would be destroyed by battle or card effect, you can destroy this card instead.", while all Scale 6 "Dinomists" have the Pendulum Effect "Before resolving a card effect that targets another "Dinomist" card(s) you control, you can negate the effect, then destroy this card. This effect can only be used once while this card is in the Pendulum Zone." Combined, two differently-Scaled "Dinomists" in your Pendulum Zones can neutralize almost any threat to the "Dinomists" in your Monster Zones at the cost of destroying themselves, allowing the monsters themselves to battle uninhibited. Their Spell & Trap Cards enable greater utility and power by searching, directly Special Summoning from the Deck, and locking down your opponent's ability to respond to battle through card effects.