splinter

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

• noun A sharp, slender piece, as of wood, bone, glass, or metal, split or broken off from a main body.
• noun A splinter group.
• intransitive verb To split or break into sharp, slender pieces; form splinters.
• intransitive verb To cause to splinter. synonym: break.

from The Century Dictionary.

• noun A sharp-edged fragment of anything split or shivered off more or less in the direction of its length; a thin piece (in proportion to its length) of wood or other solid substance rent from the main body; a splint.
• To split or rend into long thin pieces; shiver.
• To support by a splint, as a broken limb; splint.
• To be split or rent into long pieces; shiver.

from the GNU version of the Collaborative International Dictionary of English.

• intransitive verb To become split into long pieces.
• transitive verb To split or rend into long, thin pieces; to shiver.
• transitive verb To fasten or confine with splinters, or splints, as a broken limb.
• noun A thin piece split or rent off lengthwise, as from wood, bone, or other solid substance; a thin piece; a sliver.
• noun The bar to which the traces are attached; a roller bolt; a whiffletree.

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

• noun A long, sharp fragment of material; often wood.
• noun A group that formed by splitting off from a larger membership.
• verb intransitive To come apart into long sharp fragments.
• verb transitive To cause to break apart into long sharp fragments.
• verb figuratively, of a group To break, or cause to break, into factions.

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

• verb withdraw from an organization or communion
• verb break up into splinters or slivers
• noun a small thin sharp bit or wood or glass or metal
• verb divide into slivers or splinters