On my feed, there’s a post where people are freaking out on learning that it’s wheelbarrow and not wheelbarrel, and asking piteously what a ‘barrow’ is.
A barrow (without a wheel) was similar to a stretcher, giving two people the ability to carry a load. I didn’t know that! (It’s been in the English language from the 14th century, and comes from the old English word “bearwe”.)
Barrow is also the word for an ancient burial mound, interestingly. That part I knew.
I wonder if there’s a connection there —
• burial mound –>
• bier ( movable frame on which a coffin or a corpse is placed before burial or cremation or on which it is carried to the grave) –>
• stretcher (for carrying living people too, not just dead ones) –>
• barrow (for carrying whatever you like, including plants and dirt) –>
• wheelbarrow (huh, it’s easier to carry things if you add wheels…)
Editing to note, per Daniel’s comment below, this is nonsense. 
Oh well!
Pictured: Soulton Long Barrow. Another word for a barrow is a ‘tumulus.’