1. The creation of words by deriving or combining parts of other words, each with a separate meaning.
2. Sticky, tacky, adhesive.

… Zamenhof offered about nine hundred roots, and although he added some more later, Esperanto remains a language with a very small pantry of staples. This frugality, its most basic trait, is then tempered by its second most basic trait, its agglutinative nature—the construction of words by the incessant addition of prefixes and suffixes to the roots.

From the post: The dream of Esperanto bringing about world peace
Source: A language to unite humankind (