n.

1. (botany) the usually underground organ that lacks buds or leaves or nodes; absorbs water and mineral salts; usually it anchors the plant to the ground
2. (linguistics) the form of a word after all affixes are removed;
   root word, base, stem, theme, radical
   
   • thematic vowels are part of the stem
3. the place where something begins, where it springs into being;
   beginning, origin, rootage, source
   
   • the Italian beginning of the Renaissance
   • Jupiter was the origin of the radiation
   • Pittsburgh is the source of the Ohio River
   • communism's Russian root
4. a number that when multiplied by itself some number of times equals a given number
5. the set of values that give a true statement when substituted into an equation;
   solution
6. someone from whom you are descended (but usually more remote than a grandparent);
   ancestor, ascendant, ascendent, antecedent
7. a simple form inferred as the common basis from which related words in several languages can be derived by linguistic processes;
   etymon
8. the part of a tooth that is embedded in the jaw and serves as support;
   tooth root

v.

1. take root and begin to grow
   
   • this plant roots quickly
2. come into existence, originate
   
   • The problem roots in her depression
3. plant by the roots
4. dig with the snout;
   rout, rootle
   
   • the pig was rooting for truffles
5. take sides with; align oneself with; show strong sympathy for;
   side, pull
   
   • We all rooted for the home team
   • I'm pulling for the underdog
   • Are you siding with the defender of the title?
6. become settled or established and stable in one's residence or life style;
   settle, take root, steady down, settle down
   
   • He finally settled down
7. cause to take roots