I don't understand what IEnumerable<int> implies. LINQ help please.

using System.Collections.Generic;
using System.Linq;

namespace Treehouse.CodeChallenges
{
    public class NumberAnalysis
    {
        private List<int> _numbers;
        public NumberAnalysis()
        {
            _numbers = new List<int> { 2, 4, 6, 8, 10 };
        }

        public NumbersGreaterThanFive()
        {
        //declare the new IEnumerable<int>
        IEnumberable<int> listGreaterThanFive = new IEnumerable<int>(); 
        //assign it to the query
        listGreaterThanFive = for number in _numbers where number > 5 select number;
        // return it
        return listGreaterThanFive;
        }
    }
}