Sublabel

In the Minimalist Program (Chomsky 1995), a sublabel is a feature associated with a label.

Example
Suppose we have a Tense node with the following features:

T  _          _ |NOM        | |+present   | |+fin       | |-V         | |+EPP       | |2nd person | |PL         | -         -

All these features are sublabels of T. These sublabels can trigger movement to a projection of T; in this example, the EPP-feature forces movement of the subject to spec,T, and the [-V]-feature forces movement of the verb to T. The features of heads that are adjoined to a head, are also sublabels of this head; so if V adjoins to T, V's features also become sublabels of T.

Link
Sublabel in Utrecht Lexicon of Linguistics

Reference

 * Chomsky, Noam A. 1995. The Minimalist program. Cambridge, MA: MIT Press.