a start

Kazuo IshiguroのWhen We Were Orphantsを読んでいます。
'As for that Anderson himself,' he said eventually, 'that chap always gave me an uneasy feeling.
Something fishy about him.
There was something fishy about the whole damn business, if you ask me.'
No sooner had he said this than he looked up at me with a start. Then before I could respond, he began to talk again rapidly, moving us on to what he no doubt considered the safer territory of our voyage to England. Before long, he was chuckling to himself as he recounted memories of our fellow passengers, the ship's officers, amusing little incidents I had long forgotten or had not registered in the first place.
"start" は中学で習う基礎単語ですが、上の引用箇所に出てきた意味が分かりません。 仕方がないので辞書を見ます。
・Oxford English Dictionary: A sudden movement of surprise or alarm.: she awoke with a start
・Cambridge English Dictionary: a sudden movement of the body that you make when something has surprised or frightened you: She gave a start as I entered.
なるほど、こんな意味もあるのですね。この"start" は次のようにこの後の箇所でも何度も出てきました。
I found her standing at the entrance of the restaurant, looking out of the windows into Lower Regent Street. She did not notice me come up to her until I touched her arm and asked: 'Is everything all right?'
She gave a start, and I noticed little traces of tears in her eyes, which she quickly tried to mask with a smile.