What procedure would help define my jawline and connect my chin to my jaw? (Photo)

You photos do not demonstrate any abnormal pathology.  If submental fullness is an issue for you I would suggest Kybella.

Thank you for your question and for sharing your photos. There are several options for contouring the neck and define the jawline.Non surgical options include: 1) Kybella to dissolve the fatty tissue in the submental area 2) Cool-mini treatment from Coolsculpting to target the same area 3)
Adding a skin tightening device such as Ulthera or Profound to the neck
tissue in conjunction with the one of the above to further tighten the
skin. This can also help you define the jawline more.4) Dermal fillers to further help you define the jawline directly as well
as lift the cheeks and allow this to lift the jowl region and thus
further define the cheeks.Surgical options include: 1) Straight liposuction which would reduce the pinchable fat under the chin2)
Anterior neck lift with liposuction which would also allow for
tightening of the platysmal muscles in the midline to allow for tighter
neck contour3) Traditional neck and face lift which does the same as 2) but also removes some excess skin in the neck and define the jawline.I
would recommend that you visit with a board certified plastic surgeon
who offers the various options above to discuss the pros/cons of each
option and help you decide which is the best for you.

This requires well performed liposuction with skin tightening.  In my practice we combine multiple treatments to get improvement including liposuction, RF skin tightening, and botox.  Sometimes fillers are used later to further define the jawline or fat transfer during the procedure to help lift/contour.  I suggest seeing a well trained professional this requires a meticulous surgeon. Best, Dr. Emer.