Merriam-Webster Collegiate Dictionary - fluid

 I. adjective  Etymology: French or Latin; French ~e, from Latin ~us, from fluere to flow; akin to Greek phlyzein to boil over  Date: 1603  1.  a. having particles that easily move and change their relative position without a separation of the mass and that easily yield to pressure ; capable of flowing  b. subject to change or movement boundaries became ~  2. characterized by or employing a smooth easy style the ballerina's ~ movements ~ recitation of his lines  3.  a. available for various uses a ~ computer program  b. liquid 4 ~ assets  • ~ly adverb  • ~ness noun  II. noun  Date: 1661 a substance (as a liquid or gas) tending to flow or conform to the outline of its container  • ~al adjective  • ~ally adverb  • ~like adjective