Other forms: understanding, understood, understands
To understand something is to see what it means. You understand the question, understand the instructions on the box, understand why your friend has stopped answering.
It stretches from facts to people. Understanding a language is one thing; understanding a person — knowing why they do what they do — is the warmer sense, and it gives us the adjective understanding, as in an understanding boss. In careful or formal English it also means having been told: 'I understand you have been unwell' is a polite way of saying somebody mentioned it. Two grammar points come with it. The past is understood, never understanded. And understand does not sit in the continuous, so I am not understanding sounds wrong; say I do not understand.
1verbunderstandTo see clearly what something means.~89%
“I read it twice and still do not understand the second paragraph.”
synonyms: grasp, follow, comprehend
2verbknowTo know how someone feels and why they act as they do.~7%
“Nobody understands him the way his sister does.”
3verbtrueTo have been told something and take it as true.~2%
“I understand you will be leaving us in June.”
4verbagreedTo take something as agreed without it being said aloud.~2%
“Everyone understands that the money will be paid back, though nobody wrote it down.”
Shares are an estimate: a language model read 14 sentences found in the wild and placed 14 of them on a sense — a count of our sample, not a measurement of English.
Understand is under plus stand, but the under is not the one you know. In Old English, under- could mean between or among, and understandan meant something like standing in the middle of a thing. To understand was to be inside it, surrounded by it, rather than crouching beneath it. The relatives went their own ways: Dutch onderstaan means to undertake, German unterstehen means to be subordinate.
Proto-Germanic
*understandaną — to stand between, understand
Proto-West Germanic
*understandan — to stand between, understand
Old English
understandan — to understand
Middle English
understanden
English, today
understand
Built from
From Middle English understanden, from Old English understandan (“to understand”), from Proto-West Germanic understandan (“to stand between, understand”), from Proto-Germanic understandaną (“to stand between, understand”), equivalent to Old English under- (“between, inter-”) + standan (“to stand”) (Modern English under- + stand). Cognate with Old Frisian understonda (“to understand, experience, learn”), Old High German understantan (“to understand”), Middle Danish understande (“to understand”). Compare also stq understunda, unnerstounde (“to dare, survey, measure”), Dutch onderstaan (“to undertake, presume”), German unterstehen (“to be subordinate”).
Etymology from Wiktionary, CC BY-SA