Dictionary:

portative

  (pôr'tə-tĭv, pōr'-)

1. Portable.
2. Capable of or used in carrying.

[Middle English portatif, from Old French, from Latin portāre, to carry.]

A small Organ of treble flue pipes common in the 14th and 15th centuries. It was strapped to the player's shoulder and played with the right hand while the bellows was operated by the left.