This is a word that falls into the false friends category. Lectura does not mean lecture. It is closely tied with the word escritura in that it refers to reading. Lectura, escritura y arithmética. Reading, writing and arithmetic.
Lectura de las palmas would be a palm reading. But, to read is leer. The gerund reading would be leyendo. Therefore lectura is the noun reading, whereas leyendo is the verb in the gerund form, reading.
[…] mentioned before that leyendo was the gerund form of the verb leer, which means reading and to read. With the -a instead of -o it becomes the noun […]