be etched on (one's) heart

To be something that one will always remember. The day you were born is just etched on my heart—I could never forget what it felt like to hold you for the first time. The overwhelming feeling of love I had when I saw you walking down the aisle at our wedding is etched on my heart. You'd think graduation day would be etched on my heart, but I really don't remember that much about it.

be etched on (one's) memory

To be something that one will always remember. The day you were born is just etched on my memory—I could never forget what it felt like to hold you for the first time. The overwhelming feeling of love I had when I saw you walking down the aisle at our wedding is etched on my memory. You'd think graduation day would be etched on my memory, but I really don't remember that much about it.

be etched on (one's) mind

To be something that one will always remember. The day you were born is just etched on my mind—I could never forget what it felt like to hold you for the first time. The overwhelming feeling of love I had when I saw you walking down the aisle at our wedding is etched on my mind. You'd think graduation day would be etched on my mind, but I really don't remember that much about it.

cast in stone

Permanently fixed or firmly established; not subject to any amendment or alteration. Often used in the negative. The deal isn't yet cast in stone, but we're confident it will go ahead as hoped. The healthcare law looks promising, but we'll have to wait until it's cast in stone before we know exactly what it will do. Keep in mind that these blueprints are not cast in stone—they're just to give you a feel for the design.

etch (something) in(to) (something)

To cut something, such as a design or message, into some material or surface. Here, use this to try to etch your name into the glass. Don't etch your initials in your desk unless you want to get detention. A: "You guys etched a heart into the tree trunk?" B: "Yeah, 'cause we're going out, like, officially now."

etched in stone

Permanently fixed or firmly established; not subject to any amendment or alteration. Often used in the negative. The deal isn't yet etched in stone, but we're confident it will go ahead as hoped. Please tell me that rule is not etched in stone—we would be a lot more productive if we didn't have to adhere to it every time. Keep in mind that these blueprints are not etched in stone—they're just to give you a feel for the design.

etch something in(to) something

and etch something in

to erode a design or message into something, usually with acid. They etched their family crest into their good crystal. He etched in his initials.

cast in stone

Also, etched in stone. Definite, fixed, as in We may choose to stay longer-our plans aren't cast in stone, or When Carl sets an agenda you can safely assume it's etched in stone. Both expressions allude to sculpture, with the first, from the early 1500s, using the verb cast in the sense of pouring and hardening some material into a final form, and the second cutting or corroding a permanent design.

be etched on your ˈheart/ˈmemory/ˈmind

be something that you will never forget because it affected you so strongly: The image of their son holding up the championship trophy would be etched on their memories forever.