Below is a beautiful explanation of Saṃskāra 行 by Venerable Thich Nu Tinh Quang that I chance upon!
Saṃskāra (Sanskrit; Pali saṅkhāra) is a term figuring prominently in Buddhism. The word means ‘that which has been put together’ and ‘that which puts together’.
In the first (passive) sense, saṃskāra refers to conditioned phenomena generally but specifically to all mental “dispositions”. These are called ‘volitional formations’ both because they are formed as a result of volition and because they are causes for the arising of future volitional actions. English translations for saṃskāra in the first sense of the word include ‘conditioned things,’ ‘determinations,’ ‘fabrications’ and ‘formations’ (or, particularly when referring to mental processes, ‘volitional formations’).
In the second (active) sense of the word, saṃskāra refers to that faculty of the mind/brain apparatus (saṃskāra-skandha) that puts together those formations.
For more on Samskara, formations, read on.