n. & v.
n. 1 a a small part of the surface of a thing distinguished by colour, texture, etc., usu. round or less elongated than a streak or stripe (a blue tie with pink spots). b a small mark or stain. c a pimple. d a small circle or other shape used in various numbers to distinguish faces of dice, playing-cards in a suit, etc. e a moral blemish or stain (without a spot on his reputation). 2 a a particular place; a definite locality (dropped it on this precise spot; the spot where William III landed). b a place used for a particular activity (often in comb.: nightspot). c (prec. by the) Football the place from which a penalty kick is taken. 3 a particular part of one's body or aspect of one's character. 4 a colloq. one's esp. regular position in an organization, programme of events, etc. b a place or position in a performance or show (did the spot before the interval). 5 Brit. a colloq. a small quantity of anything (a spot of lunch; a spot of trouble). b a drop (a spot of rain). c colloq. a drink. 6 = SPOTLIGHT. 7 (usu. attrib.) money paid or goods delivered immediately after a sale (spot cash; spot silver). 8 Billiards etc. a a small round black patch to mark the position where a ball is placed at certain times. b (in full spot-ball) the white ball distinguished from the other by two black spots.
v. (spotted, spotting) 1 tr. a colloq. single out beforehand (the winner of a race etc.). b colloq. recognize the identity, nationality, etc., of (spotted him at once as the murderer). c watch for and take note of (trains, talent, etc.). d colloq. catch sight of. e Mil. locate (an enemy's position), esp. from the air. 2 a tr. & intr. mark or become marked with spots. b tr. stain, soil (a person's character etc.). 3 intr. make spots, rain slightly (it was spotting with rain). 4 tr. Billiards place (a ball) on a spot. in a spot (or in a tight etc. spot) colloq. in difficulty. on the spot 1 at the scene of an action or event. 2 colloq. in a position such that response or action is required. 3 without delay or change of place, then and there. 4 (of a person) wide awake, equal to the situation, in good form at a game etc. put on the spot US sl. decide to murder. running on the spot raising the feet alternately as in running but without moving forwards or backwards. spot check a test made on the spot or on a randomly-selected subject. spot height 1 the altitude of a point. 2 a figure on a map showing this. spot on Brit. colloq. adj. precise; on target.
adv. precisely. spot weld a weld made in spot welding. spot-weld v.tr. join by spot welding. spot welder a person or device that spot-welds. spot welding welding two surfaces together in a series of discrete points.
[ ME, perh. f. MDu. spotte, LG spot, ON spotti small piece ]