I interchange lunch and dinner for the midday meal.. and sometimes tea and dinner for the evening meal.. there is no standard here.
I say glad wrap.
Kids at my school don't even know what trousers are any more- they've only ever heard them be called pants (or more particularly trakkies, jeans etc)
Permanent markers (or permanent textas) are never Nikko's... but ever increasingly over the past few years they are becoming Sharpies.
I also interchange rock melon and cantaloupe- my kids know they are the same fruit.
I say runners or sneakers too... more so runners these days though.