Critter/ˈkrɪtər/ Definition 1 of 2Pro Tip 1/3Colloquial Term Used in casual conversation, not in formal writing or speech. I saw a critter scurry across the trail during our hike. Pro Tip 2/3Endearment Possible 'Critter' can sound affectionate when referencing small, cute animals. Look at that cute little critter playing in the yard! Pro Tip 3/3Often Small Animals Typically refers to animals that are smaller in size, not big ones. We have a few backyard critters, like birds and rabbits.