prophase

https://doi.org/10.1351/goldbook.11143
First phase of meiosis or mitosis in which thickening and orientation of the chromosomes occurs.
Source:
PAC, 2016, 88, 713. 'Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)' on page 797 (https://doi.org/10.1515/pac-2015-1202)