Learn in the textbookBasic Units of Data Structure
DefinitionA data item (項目, also called データ項目) is each unit, such as "Name" or "Price," into which meaningful data is divided, and in a table it means almost the same thing as a field.
ExplanationOne record is expressed as a set of values for several data items. Deciding which data items to keep is the same as deciding how the table's columns are laid out.
AnalogyIt is like each heading in a household account book, such as "Date," "Item," and "Amount." Each heading decides what gets written down.
Memory hookBoth kanji in 項目 stand for the smaller divisions of a whole. Picture each line of a bulleted list.