The main features of the festival are:[1] On that day ... the modern Egyptians say that lettuce represents hopefulness at the beginning of the spring.
As Egypt became Islamized, the term Shemu/Shom Ennisim found a rough phono-semantic match in Sham Ennesim, or "Smelling/Taking In the Zephyrs,"[2][1] which fairly accurately represents the way in which the festival is celebrated.
[1] For the festival to be collectively celebrated by the Muslim Egyptians it must have been retained by them amongst themselves after conversion, this is evident from the festival's documented history[2] (see below), and from the fact that they perform the exact same ancient Egyptian celebratory traditions,[1] as well as being evident from the fact that the festival is celebrated by Muslim Egyptians in rural areas as a tradition within families, without reference to a specific religion, and is evident from practices such as the traditional fesikh dish whose preparation is passed down within Muslim families as an occupation.
Early in the morning of this day, many persons, especially women, break an onion, and smell it; and in the course of the forenoon, many of the citizens of Cairo ride or walk a little way into the country, or go in boats, generally northwards, to take the air, or, as they term it, smell the air, which, on that day, they believe to have a wonderfully beneficial effect.
This year (1834), they were treated with a violent hot wind, accompanied by clouds of dust, instead of the neseem; but considerable numbers, notwithstanding, went out to 'smell' it.
In his book, E. W. Lane also reports: "they [the Muslims of Egypt] calculate the period of the 'Khamaseen,' when hot southerly winds are of frequent occurrence, to commence on the day immediately following the Coptic festival of Easter Sunday."
Sham Ennessim (Shemu) is an official holiday in modern Egypt celebrated by all Egyptians regardless of their religion, background or social class.