tier

Other forms: tiers

A tier is a level or a layer. If you sit in the top tier of seats at a concert, you can see the whole stage and most of the audience — but you probably have to climb lots of stairs.

A tier can describe a layer of ruffles on a dress, a section of seats in a stadium, or one layer of a fancy cake. You could also talk about a tier in terms of value or position. For example, the most popular, well-known actors might be considered part of the top tier, getting all the best parts. Tier originated from the Old French word tire: rank, sequence, or order.

Definitions of tier

1. noun

   one of two or more layers one atop another
   “tier upon tier of huge casks”

   “a three-tier wedding cake”

   type of:

   bed, layer

   single thickness of usually some homogeneous substance
2. noun

   a relative position or degree of value in a graded group
   synonyms: grade, level

   types:

   biosafety level

   the level of safety from exposure to infectious agents; depends on work practices and safety equipment and facilities

   A level

   the advanced level of a subject taken in school (usually two years after O level)

   GCSE, General Certificate of Secondary Education, O level

   the basic level of a subject taken in school

   college level

   the level of education that college students are assumed to have attained

   biosafety level 1

   exposure only to infectious agents that do not ordinarily cause human disease

   biosafety level 2

   exposure to infectious agents that can cause disease in humans but whose potential for transmission is limited

   biosafety level 3

   exposure to infectious agents that can be transmitted by the respiratory route and which can cause serious infection

   biosafety level 4

   exposure to exotic infectious agents that pose a high risk of life-threatening disease and can be transmitted as an aerosol and for which there is no vaccine or therapy

   type of:

   rank

   relative status