prophase

pro·phase

noun \-ˌfāz\

Definition of PROPHASE

1

: the initial stage of mitosis and of the mitotic division of meiosis characterized by the condensation of chromosomes consisting of two chromatids, disappearance of the nucleolus and nuclear membrane, and formation of the mitotic spindle

2

: the initial stage of the first division of meiosis in which the chromosomes become visible, homologous pairs of chromosomes undergo synapsis and crossing-over, chiasmata appear, chromosomes condense with homologues visible as tetrads, and the nuclear membrane and nucleolus disappear and which is divided into the five consecutive stages leptotene, zygotene, pachytene, diplotene, and diakinesis

—pro·pha·sic \(ˈ)prō-ˈfā-zik\ adjective

Illustration of PROPHASE