noun
Refers to the first character or letter of a word, name, or phrase. Often used in contexts like acronyms, monograms, or indexing.
名前の頭字をとってイニシャルを作る。
Take the first letters of the name to make initials.
索引では、項目の頭字で
In the index, entries are sorted by the first letter.
イニシャル is a loanword for 'initials' (often a set of letters), while 頭字 focuses on the concept of a first letter or initial character itself.
頭文字 is a more common synonym for 'first letter' or 'initial', while 頭字 is slightly more technical or formal.
Compound of 頭 (kashira, 'head; first') and 字 (ji, 'character; letter'). The reading かしらじ follows standard rendaku voicing of the second element.