Ozhegov's Explanatory Dictionary hais tias lub pentagon yog ib daim duab geometric bounded los ntawm tsib txoj kab ncaj nraim ua tsib lub kaum sab hauv, nrog rau txhua yam khoom ntawm cov duab zoo sib xws. Yog hais tias ib tug muab polygon muaj tag nrho cov tib sab thiab cov ces kaum, ces nws yog hu ua ib txwm (pentagon)