1.Definition: added to a regular schedule

Related Adjective(s):special

2.Definition: further or added

"Need extra help", "An extra pair of shoes"

Related Adjective(s):additional

3.Definition: more than is needed, desired, or required

"Found some extra change lying on the dresser", "Extra ribs as well as other supernumerary internal parts"

Related Adjective(s):excess, redundant, spare, supererogatory, superfluous, supernumerary, surplus