subtle

adj 1: be difficult to detect or grasp by the mind; "his whole

attitude had undergone a subtle change"; "a subtle

difference"; "that elusive thing the soul" [syn: {elusive}]

2: faint and difficult to analyze; "subtle aromas"

3: able to make fine distinctions; "a subtle mind"

4: working or spreading in a hidden and usually injurious way;

"a subtle poison" [syn: {insidious}, {pernicious}]

subtype

If S is a subtype of T then an expression of

{type} S may be used anywhere that one of type T can and an

{implicit type conversion} will be applied to convert it to

type T.

In {object oriented programming}, this means that {objects} of

type S must accept every {message} that one of type T would.

(1997-07-28)