Is the Korean word for "pillow" 벼개 or 베개?

 ANSWER: 베개

When I first went to Korea in the late '1970s, I thought the Korean word for "pillow" was 벼개 since that was the way most of the Koreans I met at the time seemed to say it. There were some who said 베개, but I thought that was just a regional dialect. Well, I was wrong. Now I know that I got it backwards. 베개 is the correct pronunciation, and 벼개 is not even in my dictionary.

There are two 베다 entries in my Korean-English dictionary. One means "to cut" or "to chop," and the other means "to rest one's head on (a pillow)." The suffix -개 is attached to verb stems and can translate as "a tool," as in 지우개 (an eraser), 덮개 (a quilt), and 깔개 (a rug), so the word 베개 literally means "a head-resting tool," which can translate as "pillow."

I wonder why some Koreans started saying 벼개 for "pillow" instead of 베개. Maybe they were afraid that some people might think that 베개 means "a cutting tool" instead of "a pillow" since the 베다 that means "to cut" is used more often than the 베다 that means "to rest one's head on."

I also wonder why Koreans say 베개를 베다 instead of 머리를 베다. Is it because "head" is already implied in the verb "베다"? Or is it because some people might think 머리를 베다 means "to cut off a head" since that is what 목을 베다 means? Anyway, why say 베개를 베다 instead of 베개에 베다? Is it because the preposition "on" is also implied in the verb 베다? 

So, it seems that the best translation for 베다 would be "to pillow" since 베개를 베다 could then translate as "to pillow a pillow."