Rather than an entire day, the Solstice represents a moment when the sun is northmost in the sky. Due to this, the sun will also rise and set at its most northern point on the day of the Solstice. Being the longest day of the year (in the northern hemisphere), you can expect around 15 hours of daylight.

Is the lengthier day even noticeable? Since the Winter Solstice in December, every day gets longer by only a few minutes. But overall, the span of daylight will have increased by over 7 hours since the Winter Solstice.

The word "Solstice" comes from the Latin, roughly translating to "sun standing still" in English. The beginning comes from the word "sol," meaning sun, while the end comes from the word "sistere," which means "to stand still."

Source:

https://www.space.com/summer-solstice-when-what

https://earthsky.org/astronomy-essentials/everything-you-need-to-know-june-solstice/

https://www.timeanddate.com/calendar/june-solstice.html