There are a plethora of words for user accounts, like logon, login, signon, and also the action of logging in (or logging on) or signing in.
Are there any usage guidelines here?
I found some infomation on Stackoverflow.
This is particularly useful:
login, logout, logon, and logoff are nouns or adjectives
log in, log out, log on, log off are verbs
for developers, this will probably be helpful in deciding which term to use:
Just an observation, but the more casual the site, the more likely it’s going to use Sign in/Sign out. The paradigm of a visitor making an announcement of presence to a casual gathering of people. More formal sites tend to want you to Log in and Log out. The wording suggests the clocking in for work; The paradigm of a person with an accredited level of authentication accessing a secure terminal and leaving a record of that visit in a log.