A case for containing letters; hence, a portable writing-desk or portfolio.(noun)
In printing, a type-case. See case, n., 6.(noun)
The Century Dictionary (Public Domain)
Use "letter-case" in a sentence
"Excuse me, Ladies; traversing the room, and having rubbed my eyes till I supposed them red, I turned to the women; and, pulling out my letter-case, I will show you one letter — here it is — read it, Miss Rawlins, if you please — it will confirm to you how much all my family are prepared to admire her."
"And out he pulled a letter-case, and taking out a letter, it is written in answer to one, sent to the person."
"He took out of his waistcoat pocket, as he sat in his gown, his letter-case, and said, Here, Pamela, read that when you go up stairs, and let me have your thoughts upon it; and that will let you into the affair."