in·ter·pose 
(ĭn′tər-pōz)
(ĭn′tər-pōz)v. in·ter·posed, in·ter·pos·ing, in·ter·pos·es
v.tr.
1.
a. To insert or introduce between parts: The ice interposes a barrier between the harbor and the islands.
b. To place (oneself) between others or things.
2. To introduce or interject (a comment, for example) during discourse or a conversation. See Synonyms at introduce.
3. To exert (influence or authority) in order to interfere or intervene: interpose one's veto.
v.intr.
1. To come between things; assume an intervening position.
2. To come between the parties in a dispute; intervene.
3. To insert a remark, question, or argument.
[French, from Old French interposer, to intervene, alteration (influenced by poser, to put, place) of Latin interpōnere, to put between : inter-, inter- + pōnere, to put; see apo- in the Appendix of Indo-European roots.]
in′ter·posal n.
in′ter·poser n.
in′ter·po·sition (-pə-zĭshən) n.