Pronunciation: [ba͡ɪ hˈe͡ə] (IPA) 
The phrase "by hair" refers to a very small margin, and is spelled as /baɪ hɛr/. The first syllable, "by", is pronounced with a long "i" sound (as in "pie") and the second syllable, "hair", is pronounced with a short "e" sound (as in "red"). The spelling of this phrase is straightforward, with the only potential confusion being the homophones "by" and "buy". However, when written in context, the intended meaning should be clear.
By hair is a colloquial expression used to describe a situation where one narrowly escapes or succeeds in something, typically by a very small margin or with great difficulty. This idiom draws upon the notion of holding onto something by a single strand of hair, symbolizing a precarious and fragile situation. It implies that the outcome could have easily been different had it not been for a stroke of luck or a last-minute effort.
The phrase is often employed in contexts where individuals narrowly avoid disaster, failure, or defeat. It suggests that they were on the brink of a negative outcome, but managed to achieve the desired result through sheer determination, perseverance, or a timely intervention. It can also depict a situation where someone triumphs over significant obstacles, reflecting their ability to overcome adversity or outperform competitors.
The expression "by hair" is versatile and can be used in various situations, such as sporting events, academic endeavors, business dealings, or personal challenges. It emphasizes the element of surprise, as the unexpected success or survival was achieved against the odds or without any guarantee of a positive outcome.
In summary, the idiom "by hair" describes an achievement or escape that occurs only by a very narrow margin or with great difficulty. It highlights the thin line between success and failure, emphasizing the element of luck, tenacity, or extraordinary effort required to secure the positive outcome.
The phrase "by a hair" is not derived from a single word, but rather consists of two separate components: "by" and "hair".
The term "by" can be traced back to Old English, where it was written as "be" and had a similar meaning. It has existed in various forms in different Germanic languages, and is believed to derive from the Proto-Germanic word "bi". Over time, "by" has retained its general sense of proximity or nearness.
On the other hand, "hair" comes from Middle English, where it was spelled as "heer" or "her". This term can be traced back to the Old English word "hǣr", and it is also related to similar words in other Germanic languages.
