Glaciology

Le glissement basal is basal sliding, and the adjective itself is the safe one; the trap sits next to it. English has a single everyday word, « basic », covering what is fundamental, what is stripped down and what is alkaline, and French shares those jobs out among three. De base is the ordinary one and means fundamental or standard: le vocabulaire de base, le salaire de base, un modèle de base. Basique belongs to the chemist and is the opposite of acide: une solution basique is an alkaline solution and nothing else, which is why un glissement basique would read as a slip of the laboratory rather than as glaciology. Spoken French has lately begun to use basique for something plain, as in un t-shirt basique, but never in a technical text. Basal is the scientific adjective of place, at the base of a thing: le métabolisme basal, and the sliding here. English keeps « basal » as well, but only inside a handful of fixed pairs, so the choice never has to be made at all.