Question

What is meant by MLT in physics,,,,in dimensions

Answer 1

M stands for mass
L stands for length
T stands for time
for example take force
the unit of force is Kg m s^-2
so it is dimensional formula is $M L T^{-2}$

Answer 2

M, L, and T in Physics:

There are seven fundamental units which can be used to define any physical quantity despite of its variation in nature of existence. Of all those 7 units, 3 are mostly used in the part of kinematics to define several physical quantity in terms of force, work, power, energy, and so on.

M, L, and T are those 3 unit of 7 fundamental units defining M to be the mass, L to be the length, and T to be the time. These together formed to derive the dimensional formula of a derived formula which helps to rule out bigger units without confusion.