At

Multiple Entries:
  At    at    ad-    astatine    at-  

Concise Oxford English Dictionary © 2008 Oxford University Press:
At

▶symbol the chemical element astatine.

Concise Oxford English Dictionary © 2008 Oxford University Press:
at1

▶preposition

• 1 expressing location or arrival in a particular place or position.

• 2 expressing the time when an event takes place.

• 3 expressing attendance of an educational institution or a workplace.

• 4 denoting a particular point or segment on a scale.

  ■ referring to someone's age.

• 5 expressing a particular state or condition.

  ■ expressing a relationship between an individual and a skill.

• 6 expressing the object or target of a look, shot, action, or plan.

  ■ expressing an incomplete or attempted action.

• 7 expressing the means by which something is done.

– phrases
at that in addition; furthermore.
where it's at informal the focus of fashion or style.

– origin OE æt, of Gmc origin.

Concise Oxford English Dictionary © 2008 Oxford University Press:
at2 /ɑːt, at/

▶noun a monetary unit of Laos, equal to one hundredth of a kip.

– origin from Thai.

Concise Oxford English Dictionary © 2008 Oxford University Press:
ad- /ad/ (also a- before sc, sp, st; ac- before c, k, q; af- before f; ag- before g; al- before l; an- before n; ap- before p; ar- before r; as- before s; at- before t)

▶prefix

• 1 denoting motion or direction to: advance.

• 2 denoting reduction or change into: adulterate.

• 3 denoting addition or increase: adjunct.

– origin from L. ad ‘to’.

Concise Oxford English Dictionary © 2008 Oxford University Press:
astatine /ˈastətiːn/

▶noun the chemical element of atomic number 85, a very unstable radioactive member of the halogen group. (Symbol: At)

– origin 1940s: from Gk astatos ‘unstable’ + -ine4.

Concise Oxford English Dictionary © 2008 Oxford University Press:
at-/at/

▶prefix variant spelling of ad-. assimilated before t (as in attend).