Answer: inclusion

AnswerCrossword Clue
INCLUSIONAdmittance
inclusiona fragment of older rock caught up in an igneous rock
inclusionsolid, liquid, or gas body enclosed within the mass of a mineral
inclusionsomething included
inclusionrock fragment foreign to the igneous rock in which it is embedded
inclusionbody suspended in the cytoplasm, as a granule
inclusionact of taking in to become part of a whole or group or the state of being so included