Lumbar puncture. Lumbar puncture (LP), also known as a spinal tap, is a medical procedure in which a needle is inserted into the spinal canal, most commonly to collect cerebrospinal fluid (CSF) for diagnostic testing. The main reason for a lumbar puncture is to help diagnose diseases of the central nervous system, including the brain and spine.
2. ratio-the relation between things (or parts of things) with respect to their comparative quantity, magnitude, or degree; an inordinate proportion of the book is given over to quotations; a dry martini has a large proportion of gin. proportion.
(redirected from tie) Also found in: Dictionary, Thesaurus, Medical, Legal, Acronyms, Idioms, Encyclopedia, Wikipedia. A measure of a company's ability to service its debts. It is calculated by dividing the company's earnings before interest and taxes by the total interest payable on its debts, expressed as a ratio. Investors prefer publicly-traded companies to have a middling times-interest-earned ratio.