- Progression through the third stage of prophase I in meiosis, in which crossing over occurs between a chromatid in one partner and another chromatid in the homologous chromosome.
Definition from: Gene Ontology via Unified Medical Language System at the National Library of Medicine
- The stage of meiotic prophase which immediately follows the zygotene and in which the paired chromosomes are thickened and visibly divided into chromatids.
Definition from: Merriam-Webster's Medical Dictionary by Merriam-Webster Inc.
See also Understanding Medical Terminology.