onset

C1 · Advanced Uncountable noun Medicine Technical

n. the moment when the first signs of an illness appear.

n. the initial phase of a disease or medical condition when symptoms first become apparent to the patient or clinician.

“Early onset of the disease can sometimes be managed with a better diet.”

“Clinicians noted that the early onset of symptoms in younger patients often correlated with a more aggressive progression of the underlying infection.”

C2 · Proficiency Countable noun Science Technical · Academic

n. the first part of a syllable, before the main vowel sound.

n. the initial consonant or consonant cluster of a syllable, preceding the nucleus.

“In the word 'stop', the letters 'st' form the onset.”

“The researcher analyzed how children acquire complex onsets in languages that allow three or more consonants before the vowel nucleus.”

C2 · Proficiency Countable noun Archaic · Literary

n. a sudden and fierce attack by an army.

n. a military assault or a sudden, violent attack.

“The soldiers prepared themselves for the enemy's fierce onset at dawn.”

“The fortress walls eventually crumbled under the repeated onset of the heavy cavalry and the relentless bombardment of the siege engines.”