1A (real or invented) word used as a trademark; a trademark in the form of a word (as opposed to a design, a colour, etc.). Also: a word used in a distinctive style or font as the symbol of a company, institution, etc.
A bit whose value indicates whether or not the character or location containing it is at one end of a word; a character containing such a bit.
Early 20th century; earliest use found in Encyclopaedia Britannica. From word + mark.