a function defined from data by means of a mathematical procedure in such a way that it is easy to obtain the function when the data are known, but when the procedure and data are not known it becomes very difficult to determine the original data: used in cryptography, where the data are the characters of the plain text, or message, and the trapdoor function is the cryptogram.
Present, Past, And Sometimes Perfect ParticiplesParticiples are words derived from verbs that can function as adjectives or as parts of verb phrases to create verb tenses. The two main types of participles are the present participle and the past participle. The perfect participle depends on the past participle for its forms. Participial phrases function as adjectives that modify the subjects or other nouns in sentences. The Present Participle Adding -ing …
What Are Gerunds?A gerund is a verb form that ends in -ing and functions as a noun or object in a sentence or phrase. Though a gerund may look like a verb, it doesn’t behave like one in a sentence. A gerund can act as the subject of a sentence, as the object of a preposition, or as the object of a verb. When a gerund has …
Origin of trapdoor function
First recorded in 1975–80; by analogy with a trapdoor in a floor, through which it is easier to fall than to reemerge after a fall
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019