Learn English – Terms regarding “travel allowance”

You can specify which is which by saying maternal grandparents (your mother's parents) or paternal grandparents (your father's grandparents). I know of no single word in English that makes the distinction.

Some families get around this ambiguity by referring to both sets of grandparents with different terms of affection (for example, the mother's mother might be "Nanny", while the father's mother might be "Grandma", so, when one parent says, "We'll be going to Grandma's for Christmas," the children know where they are going).

I should note that the terms maternal and paternal are seldom used. For example, in your sentence, I would simply say:

"I visited my grandmother today in the hospital."

Sometimes, though, maternal and paternal can be used for clarification:

"After the fire, Emily went to live with her grandparents for awhile, while her parents recovered in the hospital."
"Which grandparents?"
"Her maternal grandparents."

although the speaker is probably just as likely to respond with:

"Her mom's parents."

One other way this is often communicated in English is by using the phrase "on my mother's side" (or "father's side"). So, in the conversation about Emily, one might hear:

"Her grandparents on her mother's side."

Or, to use your original example:

"Today in the hospital, I visited my grandmother on my mother's side."

_{Credit and thanks to mcalex for mentioning on my mother's/father's side.}

If the original article says flour, you can assume it's talking about all kinds of flours.

As for the flour taxonomy, English typically uses adjectives to distinguish between them, such as all-purpose flour, baking flour, and bleached or unbleached flour. You can read more about these various flours at the food encyclopedia or at this 2009 blog entry. Flours can also be named after the grains they are made from (e.g., flaxseed flour or kamut flour).

Specific names for specific flours are relatively uncommon in English, although I can think of at least one notable exception:

Coarse, whole-grain rye flour is called pumpernickel, and gives its name to the traditional German bread.