A one

American  

[ey wuhn] / ˈeɪ ˈwʌn /

Also A-one,

adjective

1. noting a vessel regarded by a shipping-classification society as being equipped to the highest standard and with equipment maintained in first-class condition.

2. Informal. Also A number one. first-class; excellent; superior.

   The meals there are A one.

---

A-one Idioms  

1. Also, A-1; A-number-one. First-class, of the best quality, as in This is an A-one steak. The term comes from Lloyd's, the British insurance company, which in its 1775 shipping register designated the condition of a ship's hull by a letter grade (A, B, etc.) and of its cables, anchor, and other equipment by a number grade (1, 2, etc.). By the early 1800s A-1, the best possible grade, was being transferred to anything of superior quality.

---

Etymology

Origin of A one

First recorded in 1830–40

Example Sentences

The connection with GCM Grosvenor came about through a One Rock deal Reed and Rosenberg worked on, in which the Chicago firm co-invested: water-delivery company Primo Brands, which went public in 2024.

From The Wall Street Journal

Currently, a single transplant can require beta cells from three or four donors, while most organ transplants involve a one to one match.

From Science Daily

A notable advantage of this approach is that it works as a "one pot" experiment.

From Science Daily

Ever since a one season spell in the old Second Division in 1977-78, Tottenham have been a top-flight club - and that position has rarely been under threat.

From BBC

“Grief is not a one and done nor is it a linear process,” she says.

From Los Angeles Times