Mayonnaise n Thousand Island dressing is..

Mayonnaise often abbreviated as mayo is a thick, creamy sauce often used as a condiment. It originates from Mahon in Spain. 
It is a stable emulsion of oil, egg yolk and either vinegar or lemon juice with many options for embellishment with other herbs and spices. Lecithin in the egg yolk is the emulsifier. Mayonnaise varies in color but is often white, cream, or pale yellow. It may range in texture from that of light cream to thick.
In Spain and Italy, olive oil is used as the oil and mustard is never included. Mayonnaise makes a great sandwich spread, and it can also form the base for salad dressings. Mayonnaise is used as the base for other sauces, such as tartar sauce and thousand-island salad dressing. Aioli is garlic-flavored mayonnaise. Another classic emulsion sauce is hollandaise, which is a cooked mixture of butter, egg yolks and lemon juice.
Mayonnaise can be made by hand with a mortar and pestle, whisk or fork, or with the aid of an electric mixer or blender.
Mayonnaise is made by slowly adding oil to an egg yolk, while whisking vigorously to disperse the oil. The oil and the water in yolks form the base of the emulsion.
1 Ranch dressing is a condiment made of some combination of buttermilk, mayonnaise, salt, garlic, onion, herbs (commonly chives, parsley, and dill), and spices (commonly black pepper, paprika, and ground mustard seed), mixed into a sauce.
Sour cream is also frequently used, and some home cooks may substitute yogurt for the sour cream to create a lower fat version.
2 Salsa golf created in Argentina is mayonnaise with ketchup as well as spices such as red pepper or oregano.
3 Tartar sauce is mayonnaise spiced with pickled cucumbers and onion. Capers, olives, and crushed hard boiled eggs are sometimes included.

Thousand Island dressing is a salad dressing and condiment, a variant of remoulade and Russian dressing.
What does Remoulade mean?
Remoulade or rémoulade, invented in France, is a popular condiment in many countries. Very much like the tartar sauce of some English-speaking cultures, remoulade is often aioli or mayonnaise based. Thousand Island dressing its base commonly contains mayonnaise and can include olive oil, lemon juice, orange juice, paprika, Worcestershire sauce, mustard, vinegar, cream, chili sauce, tomato puree, ketchup, or Tabasco sauce. It also typically contains finely chopped ingredients, which can include pickles, onions, bell peppers, green olives, hard-boiled egg, parsley, pimento, chives, garlic, or chopped nuts (such as walnuts or chestnuts).
Thousand Island dressing became a standard condiment, used on sandwiches and salads.