based on a guess, estimate or theory; not existing in reality 猜测的；估计的；理论上的；想象的 My calculation is based on notional figures, since the actual figures are not yet available. 我是按估计的数字计算的，因为还没有实际数字。
Word Originlate Middle English (in the Latin sense): from obsolete French, or from medieval Latin notionalis ‘relating to an idea’, from notio(n-) ‘idea’, from notus ‘known’, past participle of noscere.