An omnivorous animal eats meat and plants — everything on the menu.
The word omnivorous wears its meaning on its sleeve: omni means "all" and vorare is "to devour" and it all comes together in the Latin word omnivorus — "all-devouring." Rarr! Polar bears are omnivorous, while pandas are herbivorous (eat only plants). People love to say they're carnivorous (eat only meat) when they're probably really omnivorous (unless they really do kick the French fries off the plate every time). Since omnivorous means to "devour everything," you can use it to describe someone with a very curious mind, who wants to "devour" everything with their brain, but not with their teeth.