What is meant by humidity ratio?

kg moisture/ kg of air

Humidity is the amount of water vapor in the air.

Humidity Ratio (X)= mw / ma   

where

x = humidity ratio (kgwater/kgair, lbwater/lbdry_air)

mw = mass of water vapor (kg, lb)

ma = mass of dry air (kg, lb)

Humidity Ratio by Vapor Partial Pressure

Humidity ratio can also be expressed with the partial pressure of water vapor:

x =0.62198 pw / (pa - pw)         (2)

where

pw = partial pressure of water vapor in moist air (Pa, psi)

pa = atmospheric pressure of moist air (Pa, psi)

Humidity Ratio is the ratio of the mass of water vapor and the mass of dry air or it is known moisture content.

It is the mass of water vapor per unit mass of dry air. The humidity ratio (W) can be calculated if the % moisture by volume (%MV) is known

amount of water vapour in atmosphere which is high  near sea shore cities

 one of the person whom ,to throughout of their laziness into their  human brain level.

  HUMIDITY RATIO =   Without lazyness /  Human brain

I agree with  Mr Mohammad shehatta answer..................     

Mass of water vapour per unit mass of dry air.

The moisture content is saturated with air