18-letter words containing sion
- post-impressionism — a varied development of Impressionism by a group of painters chiefly between 1880 and 1900 stressing formal structure, as with Cézanne and Seurat, or the expressive possibilities of form and color, as with Van Gogh and Gauguin.
- priority inversion — (parallel) The state of a concurrent system where a high priority task is waiting for a low priority task which is waiting for a medium priority task. The system may become unstable and crash under these circumstances. In an operating system that uses multiple tasks, each task (or context) may be given a priority. These priorities help the scheduler decide which task to run next. Consider tasks, L, M, and H, with priorities Low, Medium, and High. M is running and H is blocked waiting for some resource that is held by L. So long as any task with a priority higher than L is runable, it will prevent task L, and thus task H, from running. Priority inversion is generally considered either as a high-level design failure or an implementation issue to be taken into account depending on who is talking. Most operating systems have methods in place to prevent or take inversion into account. Priority inheritance is one method. The most public instance of priority inversion is the repeated 'fail-safe' rebooting of the Mars Pathfinder. base station ('Sagan Memorial Station').
- processionary moth — a moth of the family Thaumetopoeidae, esp the oak processionary moth (Thaumetopoea processionea), the larvae of which leave the communal shelter nightly for food in a V-shaped procession
- provision merchant — a person or company in the business of retailing food and other provisions
- qattara depression — a desert basin in the Libyan Desert, in NW Egypt: lowest point is 435 feet (133 meters) below sea level. 6950 sq. mi. (18,000 sq. km).
- radical expression — an expression in which radical signs appear.
- reduction division — the first division of meiosis in which the number of chromosomes is reduced to half the original number.
- regression testing — (programming) Part of the test phase of software development where, as new modules are integrated into the system and the added functionality is tested, previously tested functionality is re-tested to assure that no new module has corrupted the system.
- regular expression — 1. (text, operating system) (regexp, RE) One of the wild card patterns used by Perl and other languages, following Unix utilities such as grep, sed, and awk and editors such as vi and Emacs. Regular expressions use conventions similar to but more elaborate than those described under glob. A regular expression is a sequence of characters with the following meanings (in Perl, other flavours vary): An ordinary character (not one of the special characters discussed below) matches that character. A backslash (\) followed by any special character matches the special character itself. The special characters are: "." matches any character except newline; "RE*" (where RE is any regular expression and the "*" is called the "Kleene star") matches zero or more occurrences of RE. If there is any choice, the longest leftmost matching string is chosen. "^" at the beginning of an RE matches the start of a line and "$" at the end of an RE matches the end of a line. (RE) matches whatever RE matches and \N, where N is a digit, matches whatever was matched by the RE between the Nth "(" and its corresponding ")" earlier in the same RE. Many flavours use \(RE\) instead of just (RE). The concatenation of REs is a RE that matches the concatenation of the strings matched by each RE. RE1 | RE2 matches whatever RE1 or RE2 matches. \< matches the beginning of a word and \> matches the end of a word. Many flavours use "\b" instead as the special character for "word boundary". RE{M} matches M occurences of RE. RE{M,} matches M or more occurences of RE. RE{M,N} matches between M and N occurences. Other flavours use RE\{M\} etc. Perl provides several "quote-like" operators for writing REs, including the common // form and less common ??. A comprehensive survey of regexp flavours is found in Friedl 1997 (see below). 2. Any description of a pattern composed from combinations of symbols and the three operators: Concatenation - pattern A concatenated with B matches a match for A followed by a match for B. Or - pattern A-or-B matches either a match for A or a match for B. Closure - zero or more matches for a pattern. The earliest form of regular expressions (and the term itself) were invented by mathematician Stephen Cole Kleene in the mid-1950s, as a notation to easily manipulate "regular sets", formal descriptions of the behaviour of finite state machines, in regular algebra.
- repossession order — If a bank or building society issues a repossession order, they officially tell someone that they are going to repossess their home.
- retirement pension — income: no longer at work
- reversionary bonus — a bonus added to the sum payable on death or at the maturity of a with-profits assurance policy
- secondary emission — the emission of electrons (secondary electrons) from a material that is bombarded with electrons or ions.
- spanish succession — War of thea war (1701-14) between European powers disputing the succession to the Spanish throne
- synthetic division — a simplified procedure for dividing a polynomial by a linear polynomial.
- television cabinet — a cabinet on which a television set is placed or in which it is encased
- television company — a company that broadcasts programmes by television
- television licence — a certificate giving official permission to own a television set
- television station — station (def 8).
- the uncircumcision — the gentiles
- to cast aspersions — If you cast aspersions on someone or something, you suggest that they are not very good in some way.
- torsion-free group — a group in which every element other than the identity has infinite order.
- transmission brake — A transmission brake is a brake that operates on the transmission system of a vehicle rather than directly on the wheels.
- transmission shaft — a shaft that rotates transmitting motion from the engine to the differential gear
- wild passionflower — the maypop, Passiflora incarnata.