Absorption
Absorption is a term that is used when some element assumes a (syntactic) feature that is not usually assigned to such an element, it is said that this element absorbs that feature.
Example
Case is usually assigned to an NP, but Case can be absorbed instead by passive morphology or by a clitic pronoun (not an NP).
Comments=
At LF: rule that derives a kind of conjunction of referential indices:
... [NPi [NPj ... -> ... [NPi NPj]i,j ...
This rule accounts for cases of crossed binding at LF (see Bach-Peters paradox), and has been proposed as an account of the interpretation of multiple questions.
Link
Utrecht Lexicon of Linguistics
References
Chomsky, Noam A. 1981. Lectures on Government and Binding. Dordrecht:Foris. Higginbotham, J. & R. May 1981. Questions, Quantifiers and Crossing. Linguistic Review, 41-80. May, Robert. 1985. Logical form. MIT Press.