The definition of shok is not clear cut and is subject to dispute amongst the poskim as to whether it refers to the upper leg or the lower leg and whether the knee is included. While a woman should ideally wear a skirt at least to the knee, and sleeves at least to the elbow, there is room according to some opinions to expose less than a tefach (approximately 8 cm) above the knee or elbow.

For an in-depth discussion of the sources of the laws of tzniut, we recommend Understanding Tzniut (published by Urim), written by our rabbinic supervisor Rav Yehuda Henkin. For further discussion, see Rav Henkin's Bnei Banim volume 3 siman 26.