# Structure of a Statute — Key Drafting Terms
## Provision
A Provision is a specific clause, section or part of a legal document that lays down a rule, requirement or condition. In simple terms, a provision is a rule written in law that must be followed.
## Sub-Section
When all parts of a section are related to each other such that, when taken together, they complete the concept of that section — each part is a sub-section.
Example: Section 5 has two sub-sections:
- Sec 5(1): Scope of Total Income of a Resident.
- Sec 5(2): Scope of Total Income of a Non-Resident.
## Clause
When each part of a section is independent of the others, each such part is called a Clause.
Example: Section 10 contains exemptions of various incomes:
- Clause (1): Exemption of agricultural income
- Clause (2): Exemption of share income of a member of HUF
## Proviso
A Proviso to any section / sub-section / clause states exceptions or conditions to the main provision. It tells us:
- Where the main provision WOULD apply, or
- Where the main provision WOULD NOT apply.
Example: Sec 80GGB & 80GGC allow deduction for donations to political parties.
Proviso: Such donation shall be made in any mode other than cash.
→ The proviso restricts the deduction by adding a mode-of-payment condition.
## Explanation
An Explanation to a section / sub-section / clause clarifies the meaning or scope of the main provision.
Example: Explanation to Sec 80GGB/80GGC defines 'political party' as a political party registered under Section 29A of the Representation of People Act.