of little width, esp in relation to height or length

limited in size or scope

a narrow field of study

inflexible in attitudes or beliefs

only just sufficient or successful

a narrow majority

in speech, denoting a vowel articulated with the tongue drawn back so as to narrow the pharynx, e.g. e and i

to make or become (something) narrow or narrower

arteries narrowed by a thick deposit

(often + down) to restrict the scope or sphere of (research, an enquiry, etc)

to close (one's eyes) slightly in focusing one's attention on something

to become narrow or narrower

His eyes narrowed