Зачем в аргументах функции стоит form? JS

1.Я не понимаю что значит form в аргументе функции validation?

function validation(form){
    function createError(input,text){
        const parent = input.parentNode;
        const errorLabel = document.createElement('label');
        parent.classList.add("error");
        
    }
   let result = true;
   for(const input of allInput){
    if(input.value ==""){
        console.log("ошибка");
        createError(input, "поле не заполнено!");
        result = false;
    }
   }
   return result;
}

formValidation.addEventListener('submit',function(event){
    event.preventDefault()
    validation(this)

    if(validation(this)==true){
        alert("Форма успешно отправлена!") 
        for (let i = 0; i < openPopup.length; i++) {
  openPopup[i].addEventListener('click', function() {
    popupContainer.style.display = "flex";});
  popupContainer.addEventListener('click', function() { popupContainer.style.display = "none"});
  };  
    }
    
});

<form action="" class="form-validation"> 
            <div class="time-spending_form-input">
                <div class="time-spending_user-name">
                    <div class="input__error"><input type="text" class="time-spending-input time-spending_name" placeholder="Имя"></div>
                    <div class="input__error"><input type="text" class="time-spending-input time-spending_surname" placeholder="Фамилия"></div>
                </div>
                <div class="time-spending_user-contact">
                    <div class="input__error"><input type="text" class="time-spending-input time-spending_email" placeholder="Email"></div>
                    <div class="input__error"><input type="text" class="time-spending-input time-spending_phone" placeholder="Телефон"></div>
                </div>
            </div>
<button type="submit" class="button__reg button__reg-content time-spending-button">Зарегистрироваться</button>
            </form>