ABAP Keyword Documentation →  ABAP Glossary → 

field symbol

Symbolic name for a data object to which actual memory areas can be assigned at program runtime. A field symbol can be used as a placeholder for a data object at the operand position. A field symbol is typed either generically or fully. Field symbols are declared using the statement FIELD-SYMBOLS or the declaration operator FIELD-SYMBOL; memory areas are assigned to them using ASSIGN.

More