capillary action

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The interaction between contacting surfaces of a liquid and a solid that distorts the liquid surface from a planar shape and causes the liquid to rise or fall in a narrow tube.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The drawing of a liquid (often against gravity) into or up narrow interstices due to surface tension

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a phenomenon associated with surface tension and resulting in the elevation or depression of liquids in capillaries