NTFT so sorry if this has been mentioned, but I see mental load as the way to make it clear that each small action has a much bigger ‘thinking’ component to it, too.
So, making dinner - the act is making dinner, but before that can happen, someone needs to know what’s in the cupboards and buy anything missing, plus have everyone’s schedules in mind so they know what time to make it. They also need to know who eats what, any allergies / dietary requirements, what they’ve had the rest of the week and think about how much to make so everyone is sated without waste.
The issue is that some (many?!) partners only see the action - making dinner - but not the rest. So when couples try to share the chores and make a more even split, giving someone ‘making dinner’ as a chore needs to include all of the prep work.
It’s not about moaning about normal adult tasks, it’s about making it clear that ‘making dinner’ doesn’t begin and end with cooking the pasta.
Some people are really good at it, and it comes naturally so it’s not difficult. Others are less good at juggling all the info in their heads / calendars, so it’s harder.
Add women working more, and the brain fog that comes with pregnancy and menopause and actually it takes a lot more brain power to do it all.
Being able to name and explain the concept is, as one PP said so eloquently, the first step to making sure it’s shared.