1. [adj]  transmitting light; able to be seen through with clarity; "the cold crystalline water of melted snow"; "crystal clear skies"; "could see the sand on the bottom of the limpid pool"; "lucid air"; "a pellucid brook"; "transparent cristal"
2. [adj]  easily understood or seen through (because of a lack of subtlety); "a transparent explanation"; "a transparent lie"
3. [adj]  free of deceit
4. [adj]  so thin as to transmit light; "a hat with a diaphanous veil"; "filmy wings of a moth"; "gauzy clouds of dandelion down"; "gossamer cobwebs"; "sheer silk stockings"; "transparent chiffon"; "vaporous silks"

1. Not visible, hidden; said of a system which functions in a manner not evident to the user. For example, the Domain Name System transparently resolves a fully qualified domain name into an Internet address without the user being aware of it.

Compare this to what Donald Norman calls "invisibility", which he illustrates from the user's point of view:

"You use computers when you use many modern automobiles, microwave ovens, games, CD players and calculators. You don't notice the computer because you think of yourself as doing the task, not as using the computer." ["The Design of Everyday Things", New York, Doubleday, 1989, p. 185].

2. Fully defined, known, predictable; said of a sub-system in which matters generally subject to volition or stochastic state change have been chosen, measured, or determined by the environment. Thus for transparent systems, output is a known function of the inputs, and users can both predict the behaviour and depend upon it.