There are five basic role levels in television.
1) The smallest/lowest type of role is called under-five (U5 or U/5) which means
the actor says five lines or less in one episode.
2) Following under-five, the next level is co-star. Co-stars (i.e. waitress or bartender)
have more lines. Casting directors usually don't take under-five or co-star credits
very seriously, although there can be exceptions if it's a large co-star.
3) Next level up is guest-stars (or "guest appearances"), which means the actor
typically has more lines, a larger part, and gets paid more than co-stars. If a celebrity
chooses to take a guest appearance role, it's called a "cameo." Guest-star roles are
more beneficial for your resume and credibility than co-star or under-five roles.
4) After guest-stars are recurring roles. These are the characters that appear in
several episodes, are usually more prominent than guest-stars, and the actor is paid
more. Recurring characters are more important to the plot but they're not
necessarily the main focus in the entire series.
5) The main (lead) characters of the show are called series regulars. They appear in
nearly every episode and are paid the most in television. Generally, the more
popular the show, and the more name value you have, the more you will be paid.
Often, series regular roles are "offer only." See "Actor's Reference".
In film, the naming of these roles is phrased differently. There are only lead and
supporting roles. Lead roles are obviously the main characters and supporting roles
help move the plot along. Supporting roles range anywhere from one line to many
lines - almost a leading character.
The lowest of the "food chain" is extra/background work. Extras have no speaking
lines, move in the background, and make a scene look more realistic. Extra work
isn't only good for paying the bills; you can obtain SAG-AFTRA (Union) vouchers
and, if you're new, become familiar with a professional set. However, no legitimate
entertainment professional will consider extra work to be a "real credit." Listing
extra work as "un-credited" on your resume makes you look unprofessional.
