Defender of mankind or a modern phonetic variation
Saysha is often considered a modern phonetic spelling of Sasha, which is a Russian diminutive of Alexandra. It carries the meaning of defending or protecting humanity. As a contemporary American invention, it may also be chosen simply for its melodic sound and unique spelling.
Less common today
Saysha isn't in the latest US Top 1000. It last peaked at #7,315 in 1991.
US births per 5-year period, 1990βpresent (SSA data).