Wiktionary
alt. (context British English) (present participle of initial English) vb. (context British English) (present participle of initial English)
WordNet
See initial
adj. occurring at the beginning; "took the initial step toward reconciliation"
[also: initialling, initialled]
v. mark with one's initials
[also: initialling, initialled]
n. the first letter of a word (especially a person's name); "he refused to put the initials FRS after his name"
[also: initialling, initialled]
Usage examples of "initialling".
Spruance was receiving the dispatches not in flag plot, but on a couch in the flag mess where he sat reading a mildewy biography of George Washington, merely initialling the message board.
Jean lost ground initialling this but did some criss-cross high-cuts with a War Office file from Ross.
He worked quickly, but with care, pencilling his instructions at the foot of each page and initialling them with a regal'S.