Meanings

optional

non-mandatory attribute

optional (O) component

any type

any character

optional user facilities

to leave to take its own course

to leave to one's imagination

environmental administrator

environmental responsibility

chief executive officer

self-responsibility

top secret mission

management responsibility

leaving the remaining corrections up to the printer after having finished proofreading

combat mission

managerial liability

principal investigator

term of office

one's country of assignment (e.g. for an ambassador)