What does "とは" mean in these sentences?


I can't understand why "とは" is being used in the following sentences:

> 1)...質問があります。その質問 **とは** 、「なぜ、皆マスクをしているの？」...
>
> 2) 花粉症 **とは** 、植物の花粉によって起こるアレルギーです。




the とは particles are used to mark a definition or explanation of something.
The structure is `<thing you are going to explain/define> とは <description>`

Let's take a look at those two sentences. I've bolded the English words that
are translated from とは

So in the first sentence the speaker says,

> I have a question. That question **is** "why is everyone wearing a mask?".

the とは marks that the speaker is about the explain/define what his/her
question is.

The second sentence is the same structure. The sentence is explaining what 花粉症
(or hay fever) is.

> Hay fever **(is/can be defined as/is explained as)** the allergy to plant
> polen.

[This site](http://learnjapanesedaily.com/japanese-grammar-
dictionary/japanese-grammar-%EF%BD%9E%E3%81%A8%E3%81%AF-toha.html) does a good
job of explaining the basic uses of とは if you want to learn a little more.




the とは particles are used to mark a definition or explanation of something.
The structure is `<thing you are going to explain/define> とは <description>`

Let's take a look at those two sentences. I've bolded the English words that
are translated from とは

So in the first sentence the speaker says,

> I have a question. That question **is** "why is everyone wearing a mask?".

the とは marks that the speaker is about the explain/define what his/her
question is.

The second sentence is the same structure. The sentence is explaining what 花粉症
(or hay fever) is.

> Hay fever **(is/can be defined as/is explained as)** the allergy to plant
> polen.

[This site](http://learnjapanesedaily.com/japanese-grammar-
dictionary/japanese-grammar-%EF%BD%9E%E3%81%A8%E3%81%AF-toha.html) does a good
job of explaining the basic uses of とは if you want to learn a little more.

