Accidental, additional, appearing casually.
From an external source; not innate or inherent, foreign.
Developing in an unusual place or from an unusual source.
Not congenital; acquired.
That serves as an addition
The situation where a student who holds a qualification equivalent to part of a degree course is then accepted onto a degree course at an intermediate point, without having to start it from the beginning.
Additional credit purchased for a mobile phone.
An addition.
An additional premium paid over the initial premium in order to increase benefit values.
A serving of drink used to top up an existing glass.
A dose of epidural anesthetic added to previously injected spinal anesthetic in combined spinal-epidural anesthesia