IPA: /ˌrɛk.tɪ.lɪˈnɛr.ɪ.ti/
KK: /rɛkˌtɪlɪˈnɛrɪti/
The quality or state of being straight or following a straight line.
The rectilinearity of the path made it easy to follow.
Rectilinearity → It is formed from "rectus" (meaning straight) and "linea" (meaning line) combined with the suffix "-ity" (meaning the state or quality of). The word describes the quality or state of being straight or having straight lines.
Think of 'straight' ('rectus') and 'line' ('linea') to remember that 'rectilinearity' refers to the quality of being straight.
No commonly confused words.