porpoise noun [C]. âº a âmammal that âlives in the âsea, âswims in âgroups, and âlooks âsimilar to a dolphin but has a âshorter ârounder ânose. (Definition of porpoise from the Cambridge Advanced Learnerâs Dictionary & Thesaurus Â© Cambridge University Press). See all translations.
Definition of point of no return. 1  1 : the point in the flight of an aircraft beyond which the remaining fuel will be insufficient for a return to the starting point with the result that the craft must proceed. 2  2 : a critical point at which turning back or reversal is not possible.
What is 'Tax Return'. A tax return is the tax form or forms used to report income and file income taxes with tax authorities such as the Internal Revenue Service (IRS) in the United States. Tax returns allow taxpayers to calculate their tax liability and remit payments or request refunds, as the case may be.