A quick search of the internet tells you what it is.
A term used on basic Biology tests.
The lack of any scientific documents on the internet, that use this term, indicates it has been fabricated by an instructor to test the student.
It is easy to see how this term might fool some.
It is made up of a legitimate prefix: cyto
Cyto-: Prefix denoting a cell. "Cyto-" is derived from the Greek "kytos" meaning "hollow, as a cell or container." From the same root come the combining form "-cyto-" and the suffix "-cyte" which similarly denote a cell.
The suffix, "phase" is also legitimate and together would indicate a life phase of a cell.
But the term does not appear to be used anywhere, except on student tests.