menon was derived from the malayalam word MELEVAN (MEL means Superior and AVAN means He).Thus the title menon refers to Superior Person performing administrative duties!
Examples:Shiv Shankar MENON-India's National Security Advisor
Shashi Tharoor-United Nations Under Secretary(former)
Swami Chinmayananda(Balakrishna Menon)
N R Madhava Menon(Legal Educator,Founder of the National Law School of India,University(Bangalore)
In the western context, from where Geni has originated, the surname is the family name. In that context Menon is NOT a surname, but rather indicative of the section of the NAIR community to which the individual belongs to. Many people nowadays have abandoned adding the Menon or any of the other community names like Nair, Panicker, Kurrup, Pillay etc. to their names. A further trend is that the family names themselves have been abanded [example Shashi Taroor]. So the "modern' Malayalee has lost both his [the women folks, the keepers of the family name, rarely had such additions to their names anyway] family and community identity!
Thus searching by the 'surname' Menon is both futile - absent in most cases - and also meaningless since it will not lead you to a specific family.