1. To enclose in a capsule or other small container.
2. To put in a short or concise form; reduce in volume.

1. To treat a collection of structured information as a whole without affecting or taking notice of its internal structure. In communications, a message or packet constructed according to one protocol, such as a TCP/IP packet, may be taken with its formatting data as an undifferentiated stream of bits that is then broken up and packaged according to a lower-level protocol (for example, as ATM packets) to be sent over a particular network; at the destination, the lower-level packets are assembled, re-creating the message as formatted for the encapsulated protocol. See also ATM (definition 1).
2. In object-oriented programming, to keep the implementation details of a class a separate file whose contents do not need to be known by a programmer using that class. See also object-oriented programming, TCP/IP.