"short feature film," 1942, from feature (n.) in the cinematography sense + -ette.
Entries linking to featurette
feature n.
early 14c., "make, form, fashion" (obsolete), from Anglo-French feture, from Old French faiture "deed, action; fashion, shape, form; countenance," from Latin factura "a formation, a working," from past participle stem of facere "make, do, perform" (from PIE root *dhe- "to set, put").
Sense of "facial characteristic" is mid-14c.; that of "any distinctive part" first recorded 1690s. Entertainment sense is from 1801; in journalism by 1855. Meaning "a feature film" is from 1913. Latin factura also is the source of Spanish hechura, Portuguese feitura, Italian fattura.
-ette
diminutive word-forming element, from Old French -ette (fem.), used indiscriminately in Old French with masculine form -et (see -et). As a general rule, older words borrowed from French have -et in English, while ones taken in since 17c. have -ette. In use with native words since late 19c., especially among persons who coin new product names, who tend to give it a sense of "imitation, a sort of" (for example flannelette "imitation flannel of cotton," 1876; leatherette, 1855; linenette, 1894). Also in such words as lecturette (1867), sermonette, which, OED remarks, "can scarcely be said to be in good use, though often met with in newspapers."