One

• One
• one (wn)adj.
  1. Being a single entity, unit, object, or living being.
  2. Characterized by unity; undivided: They spoke with one voice.
• One on one,
• -My "big kids" are wild maniacs. One on one, they are sweet as can be, but they are quite the terrible twosome together. I'm hoping I can handle them and the baby all on my own...I have a feeling they will be ganging up on me.
  -
  
  1. Consisting of or being direct communication or exchange between two people: one-on-one instruction.
  2. Sports Playing directly or exclusively against a single opponent.

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  one-on-one adv.
• one by one

  Individually in succession.
• One to one...
• at one

  In accord or unity.
• one and all

  Everyone.
• Usage Note: When constructions headed by one appear as the subject of a sentence or relative clause, there may be a question as to whether the verb should be singular or plural. Such a construction is exemplified in the sentence One of every ten rotors was found defective. Although the plural were is sometimes used in such sentences, an earlier survey found that the singular was preferred by 92 percent of the Usage Panel.·Constructions such as one of those people who pose a different problem. Most grammarians would argue that who should be followed by a plural verb in these sentences, as in He is one of those people who just don't take "no" for an answer. Their thinking is that the relative pronoun who refers to the plural noun people, not to one. They would extend the rule to constructions with inanimate nouns, as in The sports car turned out to be one of the most successful products that were ever manufactured in this country. However, constructions of this sort are often used with a singular verb even by the best writers.