GST Glossary — A to Z of GST Terms

A

ARN (Application Reference Number): A unique number generated on the GST portal every time a form is submitted, used to track the status of that submission.
ASMT: The prefix for GST Assessment forms (e.g. ASMT-10 scrutiny notice, ASMT-11 reply) used in the officer-led assessment and scrutiny process.
Advance Ruling: A written decision issued by the Authority for Advance Ruling (AAR) on a specific question of GST law or fact, given in advance of a transaction, binding on the applicant and the tax officer for that case.
Aggregate Turnover: The total value of all taxable supplies, exempt supplies, exports, and inter-state supplies of a person with the same PAN, computed on an all-India basis — used to determine registration and scheme eligibility thresholds.

B

Bill of Supply: A document issued instead of a tax invoice by a person who cannot charge GST separately — typically a Composition scheme taxpayer or someone supplying exempt goods/services.

C

CGST: Central Goods and Services Tax — the component of GST collected by the central government on an intra-state (within one state) supply, charged alongside SGST.
Casual Taxable Person: Someone who occasionally supplies goods or services in a state where they have no fixed place of business — e.g. at a trade fair or temporary stall — requiring a short-term registration.
Composite Supply: A supply of two or more goods/services that are naturally bundled and supplied together in the ordinary course of business, taxed at the rate of the principal item in the bundle.
Composition Scheme: A simplified GST option for small taxpayers to pay tax at a flat rate on turnover instead of the standard rate per supply, in exchange for giving up Input Tax Credit and inter-state supply ability.
Credit Note: A document issued by a supplier to reduce the value/tax of an earlier invoice — e.g. for a sales return or a post-sale discount — which correspondingly reduces the supplier's output tax liability.

D

DRC: The prefix for GST Demand and Recovery forms (e.g. DRC-01 show-cause notice, DRC-03 voluntary payment) used in tax demand and recovery proceedings.
Debit Note: A document issued by a supplier to increase the value/tax of an earlier invoice, typically when the original invoice under-charged for the goods or services supplied.

E

E-Invoice: A B2B invoice electronically authenticated by the government's Invoice Registration Portal (IRP), which issues a unique IRN and QR code — mandatory above a turnover threshold.
E-Way Bill: An electronic document required for the movement of goods above a value threshold, generated on the GST portal before dispatch, tracking the shipment against its invoice.
Exempt Supply: A supply of goods or services on which no GST is charged, and which does not entitle the supplier to claim Input Tax Credit on related purchases — distinct from a zero-rated supply.

G

GSTIN: Goods and Services Tax Identification Number — the unique 15-digit number assigned to every GST-registered business, based on PAN and state of registration.
GSTR: The prefix for GST Return forms (GSTR-1, GSTR-3B, GSTR-9, etc.) — see our full chapter on the different GSTR forms and what each reports.

H

HSN Code: Harmonized System of Nomenclature — an internationally standardised numeric code used to classify goods, determining the applicable GST rate.

I

IGST: Integrated Goods and Services Tax — charged on inter-state (across state lines) supplies and on imports, collected by the central government and later apportioned between the states involved.
IRN: Invoice Reference Number — a unique hash generated by the Invoice Registration Portal for every valid e-invoice, without which a B2B invoice above the e-invoicing threshold is not legally valid.
Input Service Distributor (ISD): An office of a business that receives invoices for services used by its branches and distributes the corresponding Input Tax Credit to those branches via a dedicated return (GSTR-6).
Input Tax Credit (ITC): Credit for GST paid on business purchases, which can be offset against GST owed on sales — the mechanism that prevents tax from cascading through a supply chain.

J

Job Work: Any treatment or process undertaken on goods belonging to another registered person — governed by specific GST rules on movement, ITC, and time limits for the goods to be returned.

M

Mixed Supply: A supply of two or more individually priced goods/services bundled together but not naturally linked, taxed at the rate of whichever item in the bundle attracts the highest GST rate.

N

Nil Rated Supply: A supply that is taxable in principle but currently charged at a 0% GST rate — distinct from an exempt supply, which is outside the tax net entirely.
Non-Resident Taxable Person: A person who occasionally supplies goods/services in India but has no fixed place of business or residence in India, requiring a specific short-term registration and dedicated return (GSTR-5).

P

Place of Supply: The location that determines whether a transaction is intra-state (CGST+SGST) or inter-state (IGST) — governed by specific rules that differ for goods versus services.

Q

QRMP Scheme: Quarterly Return, Monthly Payment — lets smaller regular taxpayers file GSTR-1 and GSTR-3B quarterly while paying estimated tax monthly via a simplified challan.

R

RCM (Reverse Charge Mechanism): A mechanism where the recipient of a supply, not the supplier, is responsible for paying GST directly to the government — applies to specific notified categories.
RFD: The prefix for GST Refund forms (e.g. RFD-01, the standard refund application) used across all refund categories.

S

SAC Code: Services Accounting Code — a 6-digit classification code (always starting with "99") used to classify services for GST purposes, the services equivalent of an HSN code.
SGST: State Goods and Services Tax — the state government's component of GST on an intra-state supply, charged alongside CGST.

T

TCS (Tax Collected at Source): GST collected by an e-commerce operator on payments made to sellers using its platform, deposited to the government and reflected in the seller's electronic cash ledger.
TDS (Tax Deducted at Source): GST deducted by specified categories of buyers (mainly government departments and notified entities) from payments to a supplier, deposited to the government on the supplier's behalf.
Time of Supply: The point in time at which GST liability arises on a transaction — determined by specific rules (earliest of invoice date, payment date, etc.) that can differ from when goods/services actually change hands.

Z

Zero-Rated Supply: Exports and supplies to SEZs, taxed at 0% but — unlike an exempt supply — still entitling the supplier to claim (and potentially refund) Input Tax Credit on related purchases.

GST Glossary.