Definition of manner noun from the Oxford Advanced Learner's Dictionary

Oxford3000

manner

noun
ˈmænə(r)
 
; ˈmænər
 
 
1 [singular] (formal) the way that something is done or happensShe answered in a businesslike manner.The manner in which the decision was announced was extremely regrettable.2 [singular] the way that somebody behaves towards other peopleto have an aggressive/a friendly/a relaxed mannerHis manner was polite but cool. see also bedside manner3 manners [plural] behaviour that is considered to be polite in a particular society or cultureto have good/bad mannersIt is bad manners to talk with your mouth full.He has no manners(= behaves very badly).She could at least have the good manners to let me know she won't be able to attend. see also table manners4 manners [plural] (formal) the habits and customs of a particular group of peoplethe social morals and manners of the seventeenth century
Idioms

all manner of somebody/something

many different types of people or things
The problem can be solved in all manner of ways.He enjoyed interacting with all manner of different people.

in a manner of speaking

if you think about it in a particular way; true in some but not all ways
All these points of view are related, in a manner of speaking.

in the manner of somebody/something

(formal) in a style that is typical of somebody/somethinga painting in the manner of Raphael

(as/as if) to the manner born

(formal) as if something is natural for you and you have done it many times in the pastShe adapted to life on the estate as if to the manner born.

what manner of…

(formal or literary) what kind of…What manner of man could do such a terrible thing?