octan

As an adjective octan

is occurring every eight days.

As a noun octane is

any of the eighteen isomeric aliphatic hydrocarbons (C₈H₁₈) found in petroleum, especially an iso-octane 2,2,4 trimethyl-pentane; they are used as fuels and solvents.

As a noun octan

is octane.

As a proper noun octant is

octans.

As nouns the difference between octan and octas

is that octan is octane while octas is .

As nouns the difference between octan and octal

is that octan is octane while octal is (arithmetic|computing|uncountable) the number system that uses the eight digits 0, 1, 2, 3, 4, 5, 6, 7.

As an adjective octal is

(arithmetic|computing) concerning numbers expressed in octal or mathematical calculations performed using octal.

As nouns the difference between octad and octan

is that octad is a group of eight things while octan is octane.

As nouns the difference between octan and octa

is that octan is octane while octa is (meteorology) the fraction of the sky that is obscured by clouds, in eighths (one octa means that one eighth of the sky is obscured, two octas that one quarter is obscured, and so on).

As nouns the difference between ocean and octan

is that ocean is ocean while octan is octane.