n. A clitic which phonetically joins with the following word. In English, the dialectal form t' is an example. In Arabic, conjunctions and prepositions that have only one letter, such as و (wa-), always attach as a prefix to the following word.
the GNU version of the Collaborative International Dictionary of English
adj. Leaning forward; -- said of certain monosyllabic words which are so closely attached to the following word as not to have a separate accent.
The Century Dictionary and Cyclopedia
In Greek grammar, dependent in accent upon the following word: noting certain monosyllabic words so closely attached to the word following as to have no accent.
n. In Greek grammar, a monosyllabic word which leans upon or is so closely attached to a following word as to have no independent accent.