CTC, gross salary and in-hand salary
Your CTC (cost to company) is everything your employer spends on you in a year. Part of it never reaches your bank account each month: the employer's share of provident fund goes to your PF account, and gratuity, if it's included, is only paid when you leave after five or more years.
Take those out and you have your gross salary: basic salary, house rent allowance (HRA) and a special allowance that makes up the rest. Your in-hand (take-home) salary is the gross minus your own PF contribution, professional tax and income tax deducted at source (TDS).