Is a simmental a euro breed?

Yes it is. Simmentals originated from Switzerland which is a country in Europe, thus the term "European" breed. Simmentals are also referred as a "Continental breed" which is, suffice to say, a similar term to that of a European breed, but a term that sets the British breeds (which are also European) apart from the Continentals like Simmental, Limousin and Charolais. British breeds include Shorthorn, Angus and Hereford.