Some time ago, a Japanese lady came to ask me, "Sensei, kono masago wa nan desu ka (What is this Masago?)" According to her, she wanted to ask me this question for a long time and finally made it because she saw my sushi.
In Japanese cuisine, there are some food materials which contain the word "Ko" or "Go" in the end.
For example, they are Takenoko, Tarako, Tobiko, Ebiko, Kazunoko, Iriko, Mentaiko, Sujiko, Shirako, Masago, Tamago and so on.
The keyword is "Ko" meaning "Child" which imply roe or egg, too. So if you know this keyword "Ko", you can easily guess these materials can be children of something.
First Takenoko literally means "child (ko) of Bamboo (Take)." "No" in "Take-no-ko" indicates "the form of possessive" or "apostrophe S." So Takenoko is bamboo shoot!
Next, Tarako literally means "child" of "Tara (Cod)." So it is Cod Roe.
Then, Tobiko literally means "child" of "Tobi-uo (Fling Fish)" The word "Uo" meaning fish is omitted, but Flying Fish Roe is called Tobiko.
Then how about Ebiko?
Ebiko is probably most popular here since this is made in Hawaii. I had never seen this in Japan and now it has become my must-item. Ebiko indicates "Child" of "Ebi (Shrimp)" and is translated as "Shrimp Flakes."
Kazunoko (Pacific herring Roe)
Mentaiko (Pollock Roe)
Sujiko (Salmon Roe)
Shirako (Milt of Anglerfish, Salmon, Squid, Cod...)
Finally, let's see the word Masago which most Japanese don't know and there are some opinions. Of course, because all selling food here have to show its ingredients, you can find an answer in the package.
According to the package I bought at Lihue Times, it says "Capelin" called "Shishamo" in Japanese. But some Japanese Websites say, "Masago" should be "Japanese anchovy roe" Then other people insist "Masago" should be a different type of "Flying Fish Roe."
But the answer I reached was from the understanding of it's kanji "Masa." "Masa" usually means "right" but this kanji "Masa" is written as "真砂True Sand."
So Masago literally means "child (roe)" of "True Sand." That's the literal translation. However, food cannot be sand. So we need an imagination that why people use the word "Sand" for roe?
I imagined "sand" indicates "roe" is tiny like sand. Then I found out any smaller roe can be called "Masago." Here in Hawaii, Masago says "Capelin" but it can be mix of any smaller fish roe.