Adjusted gross income, or AGI, is a person's total taxable income minus allowable tax deductions and personal exemptions. Taxable income includes all wages, salaries, tips, dividend and interest income and capital gains. These incomes comprise the Income portion of many IRS tax-return forms, including Form 1040A.
An H-style cap (cowl) is a chimney top constructed from chimney pipes shaped like the letter H. (Its image is included in cowl (chimney).) It is an age-old method of regulating draft in situations where prevailing winds or turbulences cause downdraft and backpuffing.
A fuel cap for an automobile is made of metal or plastic. It secures the entry to the fuel tank. Mostly the caps have threads, which are fixed to the tank pipe with matching threads. A rubber gasket at the top gets compressed when the cap is fixed and stops the leakage of fuel.