Qué significa ''Tumbao''?

So I was watching the Latin Grammies, & Celia Cruz, first lady of salsa, comes on, singing “La negra tiene tumbao”. What’s tumbao? Anyone?

From http://www.thedrumclub.com/DRUMSET/essentialstyles/afrocuban/pt2tumbao.HTM

So I guess it’s the equivalent of saying “The lady’s got groove” or something similar…

Cool! Gracias!