blankyoudaoicibaDictYouDict[blank 词源字典]
blank: [15] Although English got blank from French blanc ‘white’, its ultimate source is Germanic. Forms such as Old High German blanc ‘white’ suggest a prehistoric Germanic *blangkaz, which could have been borrowed into Romanic, the undifferentiated precursor of the Romance languages, as *blancus – hence French blanc, Italian bianco, Spanish blanco, and Portuguese branco.

The word originally meant simply ‘white’ in English, but this sense had all but died out by the early 18th century, by which time the present-day ‘unmarked’ was well established. Other derivatives of French blanc include the verb blanch [14], from French blanchier, and blanket [13], from Old French blancquet. Blanco is a trade name (based on blanc) coined in the 1890s for a whitening preparation for military webbing (subsequently applied to the khakicoloured version as well).
=> blanch, blanket[blank etymology, blank origin, 英语词源]
blank (adj.)youdaoicibaDictYouDict
early 13c., "white, pale, colorless," from Old French blanc "white, shining," from Frankish *blank "white, gleaming," or some other West Germanic source (compare Old Norse blakkr, Old English blanca "white horse;" Old High German blanc, blanch; German blank "shining, bright"), from Proto-Germanic *blangkaz "to shine, dazzle," extended form of PIE root *bhel- (1) "to shine, flash, burn" (see bleach (v.)).

Meaning "having empty spaces" evolved c. 1400. Sense of "void of expression" (a blank look) is from 1550s. Spanish blanco, Italian bianco are said to be from Germanic. Related: Blankly, blankness.
blank (n.)youdaoicibaDictYouDict
late 14c. as the name of a small French coin; 1550s as "white space in the center of a target," from the same source as blank (adj.). Meaning "empty space" (in a document, etc.) is from c. 1570. Meaning "losing lottery ticket" (1560s) is behind the expression draw a blank. The word has been "for decorum's sake, substituted for a word of execration" [OED] from 1854. From 1896 as short for blank cartridge (itself from 1826).
blank (v.)youdaoicibaDictYouDict
1540s, "to nonplus, disconcert, shut up;" 1560s, "to frustrate," from blank (adj.). Sports sense of "defeat (another team) without allowing a score" is from 1870. Meaning "to become blank or empty" is from 1955. Related: Blanked; blanking.