Additionally, it can help to see them as "level 0" spells.

Here is the full description of them in the Player HandBook:

A cantrip is a spell that can be cast at will, without using a spell slot and without being prepared in advance. Repeated practice has fixed the spell in the caster's mind and infused the caster with the magic needed to produce the effect over and over. A cantrip's spell level is 0.

It's true that mechanics in BG3 could be better explained to people who don't know dnd. Then again, in RPG videogames, mechanics are usually implementation details that no player gets in details. :) At leat this time, there is an opportunity to understand them (the basic rules are free to obtain on dndbeyond.com, btw)