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Pentium: n.

The name given to Intel's P5 chip, the successor to the 80486. The name was chosen because of difficulties Intel had in trademarking a number. It suggests the number five (implying 586) while (according to Intel) conveying a meaning of strength “like titanium”. Among hackers, the plural is frequently ‘pentia’. See also Pentagram Pro.

Intel did not stick to this convention when naming its P6 processor the Pentium Pro; many believe this is due to difficulties in selling a chip with “hex” or “sex” in its name. Successor chips have been called Pentium II, Pentium III, and Pentium IV.