Oh, friend, I almost didn’t come back up out of the OED this morning. King Alfred used it, it has so many forms, oh, wow. I am nourished.

And almost half of our references are to the same hollow…

• 1.074 In hollow halls beneath the fells.
• 4.004 and hollow;
• 7.002 and hollows
• 12.027 in the stony hollows far above;
• 12.077 in the hollow of his left breast
• 14.020 Look for the hollow of the left breast
• 14.023 straight for the hollow by the left breast
• 15.038 In hollow halls beneath the fells.