When writing genealogy information for anyone to read, avoid using terms like "Grandma" or "Uncle" without fully identifying the person. Vague references will only confuse the reader.
The same is true when asking people questions in an interview. It took me forever to get my grandma Neill to understand that I was asking questions about HER Grandfather Trautvetter, not her dad (who was my dad's Grandpa Trautvetter).
Once you've had children, it does get a little confusing who you mean when you say "Grandma." Don't leave someone in a hundred years confused about who you meant. Be specific.