In a relational database, a column is a vertical group of cells within a table.
It’s also used to describe the vertical group of cells within a result set of a query, or other database objects, such as views, stored procedures, table-valued functions, etc.
In a table, each column is typically assigned a data type and other constraints which determine the type of value that can be stored in that column. For example, one column might email addresses, another might accept phone numbers.