Initial

initial

(chronologically first)

initial

(spatially first)

initiale

(first letter of a word)

initiale

(first letters of a person's name as a unit)

initiale

(first part of a syllable (onset))

lettrine

(first letter of a word)

lettrine

(calligraphy: distinguished initial letter)

première lettre

(first letter of a word)

parapher

(to sign one's initial(s))