Word of the Day - 07/20/26
parallax
/'pærə,læks/(n.): the apparent displacement of an object as seen from two different points that are not on a line with the object
Astronomers use stellar parallax to calculate the distance to nearby stars, observing their apparent shift against distant background objects as Earth orbits the Sun.
Word Origin
The word 'parallax' originates from the Greek 'parallaxis' (παράλλαξις), meaning 'alteration', 'variation', or 'sideways movement'. This term is derived from the Greek verb 'parallassein' (παραλλάσσειν), which means 'to change' or 'to alter'. 'Parallassein' itself is formed from 'para-' (παρά), meaning 'beside', 'alongside', or 'beyond', and 'allassein' (ἀλλάσσειν), meaning 'to change' (from 'allos' (ἄλλος), meaning 'other').
The root 'allos' (ἄλλOς), meaning 'other', also appears in words like 'allegory' (speaking of other things) and 'allergy' (a reaction to something 'other').