silicle (sil-ickle) and silique (sil-eek): two-chambered (loculed) fruits on species belonging to the mustard (Brassicaceae) family; when opened, a central septum (or wall) between locules is revealed, to which the seeds are attached.
As far as I know, the only plant family with silicles or siliques is the mustard family. I have always found it a little amusing that there are two names for essentially the same thing, the major difference being the shape. A silicle is a short, wide, flattened or rounded fruit; a silique, on the other hand, is long and narrow.
For help remembering which is which, just remember that a silique is “long and sleek”, and a silicle is everything else (heart shaped, spherical, or a flattened circle).
The photo at the top of the post is of the silicles of field pennycress (Thlaspi arvense).