(1):

(n.) A pigment. See India ink, under India.

(2):

(n.) A fluid, or a viscous material or preparation of various kinds (commonly black or colored), used in writing or printing.

(3):

(n.) The step, or socket, in which the lower end of a millstone spindle runs.

(4):

(v. t.) To put ink upon; to supply with ink; to blacken, color, or daub with ink.