interposer

noun2

1. •
   One who interposes.

   • Since I haue your good leaue to go avvay, / I vvill make hast. But till I come againe, / No bed shall ere [e'er] be guilty of my stay, / Nor rest be interposer tvvixt vs tvvain. — 1596
2. •
   An electrical interface between one connection or socket and another, used to spread a connection to a wider pitch or to reroute it.