Which part of the flag is known as the "Spade collar"?

The "Spade collar" refers to the top edge of the flag, where it connects to the pole or staff. This part is crucial because it provides stability and integrity to the flag when it is being displayed. The design typically ensures that the fabric can be securely attached to the pole, allowing the flag to wave freely in the wind without becoming detached. Understanding the function of the Spade collar helps in maintaining the flag’s appearance and performance during parades and performances, which is particularly important in color guard activities.

The other parts mentioned in the options serve different functions. The lower corner typically deals with the flag's presentation and weight distribution but does not play the same role in attachment. The support structure refers to the pole or staff itself and does not directly relate to the flag's fabric. The connecting piece could refer to various methods of attachment or design elements that might not specifically correlate with the term "Spade collar."