The Navy secretary has ordered the Marine Corps to make some of its job titles gender neutral by April following last year's historic move to open all combat positions to women.

Navy Secretary Ray Mabus sent a memo to Marine Commandant Gen. Robert Neller last week requiring a detailed plan by Jan. 15 on how he planned to integrate the service's boot camp and what he planned to rename certain job titles with "man" in the name, according to a Marine Corps Times report.

Storied titles like infantryman or midshipman will not need to be changed under the new gender neutral guidelines, but any specialty with "man" appearing as a separate word, like reconnaissance man or fire support man, will need to be updated. An official told the Marine Corps Times that in some cases, "man" could just be dropped from the titles.

Defense Secretary Ash Carter announced last year that he would open all combat positions to women with no exceptions, despite the Marine Corps asking to keep some specialties male-only.

Pentagon press secretary Peter Cook said on Tuesday that the services had submitted its implementation plan and that the working group to oversee the changes will meet for the first time this week.

All changes must be implemented by April 1, though officials acknowledge it could be years before some specialties see their first woman due to the training required.

Mabus also ordered the Marine Corps to make updates to its boot camp process, where male and female recruits train separately. Men and women in the service's Officer Candidate School already train alongside each other.

An official told the Marine Corps Times that they are looking at the logistics of fully integrating boot camp, like how many drill instructors are needed and how to house men and women in barracks together.

Mabus made it clear in the memo that simply having men and women training together on the same grounds does not meet the standard for integration.

"Co-location does not meet the requirement for gender-integrated training," he wrote.