Definition

1. Noun:
   • An operation that determines whether one or more of a set of items has a specified property: A "lookup" is the act or process of searching for and retrieving specific information from a structured collection of data, such as a list, table, or database.

Usage

• The word "lookup" is primarily used as a noun in technical and computing contexts to describe a search operation.
• It is often used with verbs like "perform," "do," or "execute" to describe the action of searching.

Examples

• Noun:
  • The software performs a fast lookup to find the customer's record.
  • Doing a dictionary lookup is a common task for language learners.
  • The reference context states: "they wrote a program to do a table lookup."

Advanced Usage

• "Lookup time": Refers to the duration or speed required to find an item in a data structure.
  • The hash table offers constant-time lookup for most operations.
• "Lookup table": A data structure, typically an array or matrix, used to pre-compute and store values for quick retrieval, avoiding complex calculations at runtime.
  • The color values were stored in a lookup table for efficient rendering.

Variants and Related Words

• Look up (phrasal verb): To search for information, especially in a reference book or database. This is the verbal form from which the noun "lookup" is derived.
  • Please look up the definition of this word in the dictionary.
• Lookup key / Lookup value: The specific piece of data (the key) used to search for associated information (the value) in a dataset.
  • The user's ID serves as the lookup key to access their profile.

Synonyms

• Search (n): The act of looking for something.
• Retrieval (n): The process of getting something back, especially information from a computer system.
• Query (n): A question or request for data, especially one submitted to a database.

Phrasal Verbs Related

• Look up (to): This is a different phrasal verb meaning to admire or respect someone.
  • I really look up to my former teacher. (This is distinct from the information retrieval meaning of "look up").

Noun

1. an operation that determines whether one or more of a set of items has a specified property
   • they wrote a program to do a table lookup