right to choose; a say; option
elective subject or course
selective; optional; alternative
multiple choice (e.g. question)
selective system; system that offers choices
elective subject; elective class
choice of nationality; choice of citizenship
selection condition; selection conditions
function preselection capability
negative selection; purifying selection
entry-information-selection
inherently optional token
frequency selective fading
selected executable test suite
selective field protection
selective abstract; slanted abstract
Switched Virtual Circuit; SVC
switched virtual connection; SVC
attribute-value-assertion
coincident-current selection
grade of delivery selection
contextually optional token
contextually optional element
frequency-dependent selection