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Cir·cu·lar a.

1. In the form of, or bounded by, a circle; round.

2. repeating itself; ending in itself; reverting to the point of beginning; hence, illogical; inconclusive; as, circular reasoning.

3. Adhering to a fixed circle of legends; cyclic; hence, mean; inferior. See Cyclic poets, under Cyclic.

*Had Virgil been a circular poet, and closely adhered to history, how could the Romans have had Dido?* --*Dennis.*

4. Addressed to a circle, or to a number of persons having a common interest; circulated, or intended for circulation; as, a circular letter.

*A proclamation of Henry III., . . . doubtless circular throughout England.* --*Hallam.*

5. Perfect; complete. [Obs.]

A man so absolute and circular

In all those wished-for rarities that may take

A virgin captive. --*Massinger.*

**Circular are**, any portion of the circumference of a circle.

**Circular cubics** Math., curves of the third order which are imagined to pass through the two circular points at infinity.

**Circular functions**. Math. See under Function.

**Circular instruments**, mathematical instruments employed for measuring angles, in which the graduation extends round the whole circumference of a circle, or 360°.

**Circular lines**, straight lines pertaining to the circle, as sines, tangents, secants, etc.

**Circular note****or Circular letter**. (a) Com. See under Credit. (b) Diplomacy A letter addressed in identical terms to a number of persons.

**Circular numbers** Arith., those whose powers terminate in the same digits as the roots themselves; as 5 and 6, whose squares are 25 and 36. --*Bailey.* --*Barlow.*

**Circular points at infinity** Geom., two imaginary points at infinite distance through which every circle in the plane is, in the theory of curves, imagined to pass.

**Circular polarization**. Min. See under Polarization.

**Circular sailing** *or* **Globular sailing** Naut., the method of sailing by the arc of a great circle.

**Circular saw**. See under Saw.

In·fin·i·ty n.; *pl.* Infinities

1. Unlimited extent of time, space, or quantity; eternity; boundlessness; immensity.

*There can not be more infinities than one; for one of them would limit the other.* --*Sir W. Raleigh.*

2. Unlimited capacity, energy, excellence, or knowledge; as, the infinity of God and his perfections.

3. Endless or indefinite number; great multitude; as an __infinity__ of beauties.

4. Math. A quantity greater than any assignable quantity of the same kind.

Note: ☞ Mathematically considered, infinity is always a limit of a variable quantity, resulting from a particular supposition made upon the varying element which enters it.

5. Geom. That part of a line, or of a plane, or of space, which is infinitely distant. In modern geometry, parallel lines or planes are sometimes treated as lines or planes meeting at infinity.

**Circle at infinity**, an imaginary circle at infinity, through which, in geometry of three dimensions, every sphere is imagined to pass.

**Circular points at infinity**. See under Circular.

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