peer / pier are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
peer: (noun) a person who is of equal standing with another in a group. (noun) a nobleman (duke or marquis or earl or viscount or baron) who is a member of the British peerage. (verb) look searchingly.
pier: (noun) a platform built out from the shore into the water and supported by piles; provides access to ships and boats. (noun) (architecture) a vertical supporting structure (as a portion of wall between two doors or windows). (noun) a support for two adjacent bridge spans.
peer: p·IH·r
pier: p·IH·r
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)