confusion

when can we say clause and when can we say subsection.eg, 2(20) section 2 clause/subsection 20

I wanna know difference between two and why is that difference.


PLEASE help me.

, If the section starts with some wording i.e if something is written at the start of a section and which is followed by.. 1... 2.... 3.. then it will be "clause". like section 2 stats with "In this Act, unless the context otherwise requires,—"and thereafter 1, 2, 3.. are given which are "clauses" not sub section. however if you look at section 139 which is followed by sub section 1 i.e nothing is written after section 139 and sub section 1 starts just after 139, in that case it will be sub section 1 of section 139. Section 2, Section 10 all are having clauses only, no sub sections are there.