### Punctuation

"Period" is the name of the punctuation mark used to indicate the end of a sentence. (there! see that one! (these last two were exclamation points, though))

### Menstruation

"Period" is a slang term, or euphemism, for the part of a woman's menstrual cycle where she is bleeding.

### Society for Creative Anachronism

In the SCA, "period" refers to the time period that is studied by the members ("pre-17th Century," to be specific).

### Cycles

"Period" is the amount of time it takes an object in orbit to return to its starting location. Also used with pendulums and other things with cycles, such as economics.

Within Conway's Life, the period is number of generations that it takes for something to re-appear in its original form. In its true form, this applies only to oscillators and spaceships. The most common oscillator is that of the blinker which has a period of 2:

```...    .o.    ...
ooo -> .o. -> ooo
...    .o.    ...
```
still life is considered to have a period of 1.

The term of period can be applied to other arrangement of cells within Conway's life that don't exactly fit the definition of a true period - a puffer, wick, fuse, superstring, stream of spaceships, factories, and guns all exhibit something that resembles a period. However, in these cases, the arrangement of cells after one period isn't exactly the same - something has changed. With puffers, guns, and factories, something has been produced (see glider gun for an example - it is period 30), while wicks, fuses, and super string contain fewer cells. Thus, these periods are considered pseudo-period rather than a true period.

A period is also a horizontal row in the periodic table of elements.

Pe"ri*od (?), n. [L. periodus, Gr. a going round, a way round, a circumference, a period of time; round, about + a way: cf. F. p'eriode.]

1.

A portion of time as limited and determined by some recurring phenomenon, as by the completion of a revolution of one of the heavenly bodies; a division of time, as a series of years, months, or days, in which something is completed, and ready to recommence and go on in the same order; as, the period of the sun, or the earth, or a comet.

2.

Hence: A stated and recurring interval of time; more generally, an interval of time specified or left indefinite; a certain series of years, months, days, or the like; a time; a cycle; an age; an epoch; as, the period of the Roman republic.

How by art to make plants more lasting than their ordinary period. Bacon.

3. Geol.

One of the great divisions of geological time; as, the Tertiary period; the Glacial period. See the Chart of Geology.

4.

The termination or completion of a revolution, cycle, series of events, single event, or act; hence, a limit; a bound; an end; a conclusion.

Bacon.

So spake the archangel Michael; then paused, As at the world's great period. Milton.

Evils which shall never end till eternity hath a period. Jer. Taylor.

This is the period of my ambition. Shak.

5. Rhet.

A complete sentence, from one full stop to another; esp., a well-proportioned, harmonious sentence.

"Devolved his rounded periods."

Tennyson.

Periods are beautiful when they are not too long. B. Johnson.

⇒ The period, according to Heyse, is a compound sentence consisting of a protasis and apodosis; according to Becker, it is the appropriate form for the coordinate propositions related by antithesis or causality.

Gibbs.

6. Print.

The punctuation point [.] that marks the end of a complete sentence, or of an abbreviated word.

7. Math.

One of several similar sets of figures or terms usually marked by points or commas placed at regular intervals, as in numeration, in the extraction of roots, and in circulating decimals.

8. Med.

The time of the exacerbation and remission of a disease, or of the paroxysm and intermission.

9. Mus.

A complete musical sentence.

The period, the present or current time, as distinguished from all other times.

Syn. -- Time; date; epoch; era; age; duration; limit; bound; end; conclusion; determination.

Pe"ri*od (?), v. t.

To put an end to.

[Obs.]

Shak.

Pe"ri*od, v. i.

To come to a period; to conclude. [Obs.] "You may period upon this, that," etc.

Felthman.