csc (cosecant) is the reciprocal of sine, so it is hypotenuse over opposite side to the angle
cos is adjacent side to the angle over hypotenuse
cot is the reciprocal of tangent, so it is adjacent side to angle over opposite side to angle
Let's use H to represent hypotenuse, O to represent opposite, and A to represent adjacent
H/O*A/H=cancel(H)/O*A/cancel(H)=A/O rarr A/O represents cotangent