点頭 is read as てんとう (tentou) and means nodding.
てんとう
tentou
てん
"dot" stroke (in a Chinese character)
てんすう
number of items
てんか
ignition
てんこ
roll-call
つく
to be turned on (of a light, appliance, etc.)
つける
to turn on
てんじ
braille
てんざい
being dotted about
てんさ
point spread
てんとり
competition for school marks
てんけい
persons or animals added to a picture
てんぽん
book with reading aids (such as kana or punctuation marks)