his·tol·o·gy 
(hĭ-stŏlə-jē)
(hĭ-stŏlə-jē)n. pl. his·tol·o·gies
1. The anatomical study of the microscopic structure of animal and plant tissues.
2. The microscopic structure of tissue.
his′to·logi·cal (hĭs′tə-lŏjĭ-kəl), his′to·logic adj.
his′to·logi·cal·ly adv.
his·tolo·gist n.