mobility (n.) Look up mobility at Dictionary.com
early 15c., "capacity for motion," from Old French mobilité "changeableness, inconsistency, fickleness," from Latin mobilitatem (nominative mobilitas) "activity, speed," figuratively "changeableness, fickleness, inconstancy," from mobilis (see mobile (adj.)). Socio-economics sense is from 1900 and writers in sociology.