Securities transaction tax: levied on specified purchases and sales of equity shares, derivatives and equity fund units on recognised exchanges. Section 97 defines key terms for the Securities Transaction Tax regime, cross referencing meanings from the Income tax Act, the Securities Contracts (Regulation) Act and SEBI regulations, and specifies taxable securities transaction to include purchases or sales of equity shares, derivatives, and units of equity oriented funds or certain business trust units on a recognised stock exchange, as well as specified sales following public offers and certain fund unit redemptions to Mutual Funds or insurance companies.