defining
feature
The defining feature of the region's landscape is the towering reddish rock formations.
The defining feature of the 1960s was liberation.
Her hair has always been one of her most defining features.
The programme's defining feature, for me, is its abundance of male bonding.
SMART Vocabulary: related words and phrases
Very important or urgent
all-important
at all costsidiom
be a matter of life and/or deathidiom
cardinally
chief
imperative
last but not leastidiom
leading
life-altering
life-and-death
life-changing
overriding
primary
prime
principally
prior
prized
seminal
tectonic
weighty