from The American Heritage® Dictionary of the English Language, 4th Edition
- prep. On top of; to a position on; upon: The dog jumped onto the chair. See Usage Note at on.
- prep. Informal Fully aware of; informed about: The police are onto the robbers' plans.
- adj. Mathematics Of, relating to, or being a mapping such that every element of the target set referred to is the image of an element in the domain.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- prep. Upon; on top of.
- prep. Aware of.
- prep. Being an onto function with a codomain of (see below).
- adj. Assuming each of the values in its codomain; having its range equal to its codomain.
from the GNU version of the Collaborative International Dictionary of English
- prep. upon; on; to; -- sometimes written as one word, onto, and usually called a colloquialism; but it may be regarded in analogy with into.
- prep. On the top of; upon; on. See On to, under on, prep.
from The Century Dictionary and Cyclopedia
- An obsolete form of unto.
- Toward and upon: as, the door opens directly onto the street.
- To and in connection with.
- To the top of; upon; on.
Sorry, no etymologies found.