Yes, it's a linguistics term. Animate things are perceived as having human-like agency. Many languages have a grammatical category clustering things like large non-human animals, the weather, or fire, or trees, together with humans. Animate. Everything else is inanimate and presumably less alive.
In English, many animals are referred to with "he" or "she". Being a mammal, large, being domesticated, being familiar, are all more likely to be animate rather than inanimate. A pet mare is going to be "she". Insects are always "it". Livestock or a reptile might get either. Babies sometimes get treated as inanimate. ("Is it a boy or girl?")
When I first learned English in school (almost 40 years ago) I was told that very young babies were grammatically neuter. Now I never hear anyone using “it” for a baby.
Has English changed in the last decades, or was my teacher wrong?
I was loudly corrected on this subject (that is, I had used "it," and he asserted that I was wrong) by a drill instructor in Marine Corps basic training a little more than a decade ago.
I'm not quite sure how much credence to give his opinion considering that his expertise was in pain, misery, and shooting guns rather than linguistics and grammar, but he certainly had strong beliefs on the subject, and I wasn't going to try to convince him otherwise.
It can be considered an insult to get the sex of a baby wrong because males are generally considered more valuable than females. It's socially better the refer to an infant as inanimate than to mistakenly refer to a male child using the female gender. That said, as soon as one knows the correct sex (often indicated by the colour of cloth used in swaddling or clothing, or other markers like design patterns of trucks or ponies, as appropriate) it's important to start using the corresponding grammatical gender otherwise the early indoctrination lacks the enforcement required for a lifetime of identity with arbitrary social constructs like masculinity and femininity.
In English, many animals are referred to with "he" or "she". Being a mammal, large, being domesticated, being familiar, are all more likely to be animate rather than inanimate. A pet mare is going to be "she". Insects are always "it". Livestock or a reptile might get either. Babies sometimes get treated as inanimate. ("Is it a boy or girl?")