The 80th anniversary is called the OAK anniversary. The traditional gifts associated are made out of oak. this can be a chair, chest, picture frame, or anything else.
Oak
Oak
platinum
Your 80th birthday is commonly referred to as your "octogenarian" birthday.
orange
A traditional gift for an 80th birthday is an emerald, but there is no specific stone associated with an 80th birthday. Ruby is also commonly associated with milestone birthdays, including 80th birthdays.
Platinum year
diamond jubilee
"Happy 80th birthday!" in English is Auguri di buon ottantesimo compleanno! in Italian.
It's the Ruby Anniversary
A 75th birthday anniversary is commonly referred to as a "diamond jubilee."
A 90th birthday anniversary is commonly referred to as a "90th birthday" or a "90th birthday celebration." Some people may also call it a "ninetieth birthday" or a "90th birthday milestone."
a scratchbook of all the flashbacks
It is the Diamond Anniversary. This dates to the Diamond Jubilee of Queen Victoria (1897). 25 = silver 50 = golden 60 = diamond (originally 75th) 70 = platinum (UK - it is 20th in the US)
There is no difference, but birthday would definitely be the more widely accepted label. The word "birthday" itself is elegant - it accurately gets the point across with four less syllables than birth anniversary.