1 [noncount] : the quality of being transparent: such as
a : the quality that makes it possible to see through something
the transparency of a piece of glass
b : the quality that makes something obvious or easy to understand
the transparency of their motives
He says that there needs to be more transparency in the way the government operates.
2 [count] : a piece of thin, clear plastic with pictures or words printed on it that can be viewed on a large screen by shining light through it
The professor used transparencies and an overhead projector during her lectures.