Does the word 東雲 shinonome have some stylistic pecularities? What's the difference between this word and others with the same meaning "daybreak; dawn"?
東雲(しののめ) is an old Japanese word that means the sky turning into a madder red color before sun-rise. According to Chiebukuro, the origin of the word is the light of the morning sun coming through 篠の目 ‐ the mesh of a window cover and door made of gregarious small bamboo grass - 篠（しの）.
The word is obsolete today, except being left as the name of area crammed with high-rise office buildings and luxury apartment houses in Edogawa-ku, Tokyo.
We can find the word, 東雲 in use only in old 和歌 these days. Here are some of them with my poor translation, which I’m afraid of totally spoiling their exquisite flavors:
つれなさを 恨みも果てぬ 東雲に 取りあへぬまで 驚かすらむ.－源氏物語 第13文, (Genji-monogatari Chapter 3.) - While I cannot complain enough about your heartlessness, look, the sky started to grow light.
「東雲のほがらかと明け行けば己が衣着ぬなる ‐ 古今和歌集 恋の歌 (Kokinwaka-shu : Love songs 637. - It’s sad that we have to wear each separate clothes and I have to go out, now that the sky started to grow light.
たぐひなくつらしとぞ思ふ秋の夜の月をのこして明くるしののめ - 千載集 (Senzai-shu 300）. - The night was so short. I cannot compare my sadness of seeing dawn light with anything else, while the moon is still hanging in autumn sky.
You need to understand that these poems were written in 平安時代 - Heian era (9-12 Century), when ”通い婚” was a common practice, where a married couple don’t live togetner under the same roof, and the husband should visit the wife in her house in the evening and leave out there before the dawn.
東雲【しののめ】 fell out of use many years ago, and it's marked as a 古語 (archaic word) in dictionaries.
Originally, 東雲 referred to a short period of time when the sun is not yet visible but the sky is already bright (after 暁【あかつき】and before 曙【あけぼの】, according to this entry).
暁 and 曙 are literary words which are still sometimes used to refer to dawn in modern Japanese, but I don't think ordinary people can explain the difference.