Tenbagger means a stock which is worth ten times its original purchase price. The term was coined by Peter Lynch in his book One Up On Wall Street (1989), adapted from baseball where "bag" is a colloquial term for "base", and extra-base hits like doubles, triples, and home runs are called two-, three-, or four-baggers.
Additional meaning of Tenbagger:
Tenbaggers are very rare investments, examples for them are Hewlett-Packard and General Electric.