nonillion

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The cardinal number equal to 10³⁰.
• noun Chiefly British The cardinal number equal to 10⁵⁴.

from The Century Dictionary.

• noun The number produced by involving a million to the ninth power, denoted by unity with fifty-four ciphers annexed; or, according to the French and American system of numeration, the number denoted by unity with thirty ciphers annexed.

from the GNU version of the Collaborative International Dictionary of English.

• noun According to the French and American notation, a thousand octillions, or a unit with thirty ciphers annexed; according to the English notation, a million octillions, or a unit with fifty-four ciphers annexed. See the Note under numeration.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun US 1030.
• noun 1054.
• noun hyperbolic An unspecified very large number.