Aim means the source of creation.
Hrim means Lakshmi is the the supreme Sakti of Vishnu, which bestows on the adept all desired objects.
Klim means great bliss, auspiciousness and knowledge bestowed on the adept.
Each diety has two forms, the visualised and the sonic which is the mantra. Each and every matrika represents divine energy. Matrikas are defined as tiny mothers who represent the deep roots of each vibration of sound from which letters, words and language are constructed. You can experience the power of the words.
Aim Hrim Klim.