z-kh-r — to remember
ז.כ.ר (zakhar) is remembering as an act rather than a mental state — the root behind zikaron, Yizkor, Yad Vashem's zekher, and the Shabbat command to remember.
The word family
Every word below is built on ז.כ.ר. Same three letters, different vowels and prefixes.
In the text
זָכוֹר אֶת־יוֹם הַשַּׁבָּת לְקַדְּשׁוֹ
Zakhor et yom ha-shabbat l'kadsho
Remember the Sabbath day, to keep it holy.
What I tell students about this root
Biblical remembering is something you do, not something you feel. When God "remembers" Noah the next thing that happens is wind over the water. So a command to remember Shabbat is not asking you to keep a date in mind — it is asking for an action that makes the day present.