n.
1.a qualitative change
2.(mathematics) a function that changes the position or direction of the axes of a coordinate system
3.a rule describing the conversion of one syntactic structure into another related syntactic structure
4.(genetics) modification of a cell or bacterium by the uptake and incorporation of exogenous DNA
5.the act of changing in form or shape or appearance
Idiom of the Day
have a head for (something)
to have the mental capacity for something
My father has a head for numbers and is very good at mathematics.